Now that we finally got the trailer there are a lot of questions. We tried to summarize all the information we have to write a more or less complete analysis of the trailer and a collection of all our theories (which can proof right or wrong) that came up during watching the video.
Please keep in mind that this analysis may contain spoilers. If it’s a major spoiler we marked it like this:  and will put the spoiler to the end of the entry so you can either read it or just leave it by that.
If you also have some theories and ideas, please let us know in the comments as we would really like to hear them.
First of all we have Clary waking up and standing at a place which looks like Lilith’s apartment. This means it’s still existent in this moment. Maybe it as been saved by either Lilith with the last power she had or by Jonathan we see “in the flesh” in the next second. 
We see Jonathan in the forest. This can be either near Idris or it could also be in the Seelie Realm (which is our guess because of a later scene). Since Alec seems to be surprised by the wings it’s probably the first time the Shadowhunters actually see Jonathan with wings. It could even be the first time for Jonathan himself.
This moment could be the resurrection and Clary seeing Jonathan alive for the first time.
This is still Lilith’s apartment Jonathan is in. From a behind the scenes photo we know that Clary is with him. We think it might either be a scene in which Jonathan realises that his mother is gone or later through 3B 
We see Magnus, Alec and Simon coming out of a portal just to find something or someone on the floor. This scene might be in connection with a later one in which Jace is fighting a demon. 
Jace is fighting with a random Seelie knight (or maybe not so random at all since Tood confirmed he was one of those at the prison in 3×09). We can be pretty sure about the episode since the actor of the Seelie knight only appears twice during 3B 
The most precious dance scene. Maybe it’s a dream  or it could also be some training for a certain event.
Clary is opening a portal in the middle of a club. We know Jace is with her from a later scene.
We see Alec and Izzy fighting against the Seelie knight we have seen before in the fight with Jace. This is happening in the back allies of the Hunter’s Moon. Why are the Seelies fighting against the Shadowhunters? 
In the following scenes a lot of things are going on with Alec and Magnus.
One of these things is Magnus being healed by a black woman. 
Simon is lying on the ground in the Seelie Court and Izzy is giving him of her blood. This should be related to the scene of Simon we saw before.
Simon and Izzy are kissing and we hear Izzy saying “You have so much more to live for”. This could happen before or after the Seelie Court scene.
Clary is back at the Institute which implies it should happen at a later point during 3B. 
Back at the Institute. Brother Zachariah is speaking, like actually speaking. Why can he do that and why is he still wearing the Silent Brothers’ robe then? He announces something but at this point we can’t be sure about what it is. It could be the wedding that has been spoiled before on Twitter.
It could also be a dream. At this point we have no idea if this is even real.
Jace’s guilt brings him to self destructive behaviour. This might happen in 3×11 as we know already from the last seconds of 3×10 that a lot is going on inside of him right now.
Connected to the club scene with the portal before. This time we see Jace clearly being with her.
Clary: “This is who I am.” It could be connected to the club scene we saw before.
And again we might be in the Seelie Realm. This scene could also be connecte to the ones with Jonathan and the wings, the fight with the swords and Jace trying to stab Clary.
You remember the demons from before? Seems like we’re in Edom again. Clary is also with Jace, Alec and Izzy. It could be here that Clary uses the sun rune we have already seen. Also, did you notice? Alec changed a bit about his bow…
This could be a dream sequence in which Jonathan says “Join me”. This could happen right after 3×10. Clary is most likely unconscious. Maybe it’s right before she’s under Jonathan’s control?
And with this the trailer ends. We hope we didn’t spoil too much but we tried to keep all the heavy spoilers below.
Let us know if there’s anything to add, any more theories or whatever else.
Read on for spoiler!
We warned you. It’s your own choice!
 Our theory is that this scene might occur at the end of 3×11 since until then everyone thinks Clary is dead. It’s just by the end of the episode that we might see her.
 As we know the books and also know Jonathan and Clary will be in Paris during the show as well, we can also guess that the scene might show up when they have been found.
 Also, the portal is made by Magnus for sure. Which means he got his magic back but it should happen at a later point during 3B.
 Magnus might have his powers back at this point. So it should be in a later episode and after the training scene for sure. But it could also be about something else. We will talk about that during .
 And this is episode 3×11 or 3×16. From BTS photos we know that Alec will also show up during this scene so he’s following Jace. And if anyone is interested: he Seelie knight is played by Jason Gosbee.
 As we know Aline only shows up once we know this is 3×21, the episode which is called “Alliance” and also discribed with “The Mission”. We also know there will be a wedding episode and we guess it might be this one since it has the biggest cast.
 Please have a closer look at the demon. Doesn’t it look like it had blond hair like Jace? And isn’t there something on it’s arm? Could it be that it took the shape of Jace since he is led by guilt and self-hatred?
 From the trailer we know Magnus is at the end of all his powers at least once. So it could be a dream of him during being unconscious or also a dream of Alec when going to Edom with Jace, Izzy and Clary to find Magnus. Magnus? Huh? Don’t worry. We’ll talk about that later
 And most definitely the scene in which he loses the Mark of Cain. This should be episode 3×14 “A Kiss from a Rose”
 Jonathan and the Seelie Queen (he name is Amara at this point) might have a pact and so they fight the Shadowhunters together.
 From #SHTVFlockToUnlock teasers we know Heidi’s story during 3B can be described with the word “power”. This means – after Raphael is gone at this point – she can lead the vampire clan, which, we can all agree on that, is not a good thing. We know Luke will hand over his Alpha rank to Maia (from later trailer scenes) so this could be after a fight (between the leaders) with Heidi which Maia won and now she’s burning her body.
 It could either be Lanaia or Catarina who is healing him. As Lanaia is showing up in episode 3×16 which is called “Stay with me” and “The dance” it might really be Lanaia who is trying to get Magnus back. During this time Magnus could have the dream about the dance.
 Theory: Magnus was abducted and brought to Edom. Alec – more than anyone else of course – is scared about losing him since Magnus can’t do much at this point as he might not have is magic back, yet. Also, do you remeber the scene in which Magnus said “It’s good to be back”? This could also be right after Edom.
 Or it could also happen during Clary being herself because the connection to Jonathan is corrupted. Anyway the scenes are probably not connected and as far as we know it could also be a dream sequence.
 This could be connected to (Warning: MAJOR AUCTION SPOILER) the letter Clary has written to Jace. Maybe at this point she is back to her usual self and knows now about the consequences she has to face for what she has done during the time she has been with Jonathan.
 And we see some special sword which could be Glorious and the Morgenstern Sword.
 Someone could have stabbed her with Glorious so Clary loses the connection to Jonathan and the demonic part dies in her.
 Read spoiler  for that