Okay so basically idk if you have seen Loki before (you probably have lol) so its just like time travel in any other movie, you got the past,present,future.

Smart Hulk once said this:

“Time doesn’t work that way. Changing the past doesn’t change the future. Think about it, if you travel to the past, that past becomes your future and your former present becomes the past, which can’t now be changed by your new future.”

Which.. doesnt make much sense. (to me anyway, and im a geek for time travel lol) so.. How I interpret it, is, so lets say, you were at the park (idk lol) and you were playing with a ball. a base ball., okay? so 1 day from now, you find a time machine and travel back in time to where you were, back in the park. Well, you are in the future traveling back to the past. so basically, if you think about it, it DOES make sense! the future is the past because you traveled to the past, does that make sense? So, maybe you could come up with a better explanation than that but thats just my thinking. Heres something else I found while doing research (BTW just found this out, if you want more info on time travel you can go to ON THIS WIKI! go to this link: https://marvelcinematicuniverse.fandom.com/wiki/User_blog:Marvelus/Time_Travel_Rules_in_the_Marvel_Cinematic_Universe

Time Travel Rules in the Marvel Cinematic UniverseMarvel Cinematic Universe Wiki

So that link will take you to where I'm getting most of my info.

Heres some cool things i found while doing research.

In the Marvel Cinematic Universe, the Time Travel follows the quantum mechanics interpretation that the universe is always splitting into parallel universes. Therefore, change/alter the past by going into the past, a new reality branches off.

Essentially, every time displacement to the past in your own timestream creates a new timeline.

If you move forward in your timestream, your arrival will not create a new timeline.

The return to the present by using your time machine will not create a new timeline either.

When a reality branches off from the timeline, this new reality will follow the exact same path of the timeline it branched off from.

If the time-traveller causes "ripples" and makes sure the course of history in this new timeline (created since the arrival) follows the same path, this new reality would be exactly the same to the one it branched off from. If the time-traveller causes "waves" this new timeline will be completely different from the one it branched off and will follow its own independent path.

The story of your reality is unalterable. The Infinity Stones create what we perceive as the flow of time, the story of our reality.

The Infinity Stones keep the flow of time intact, if they are taken out of the universe, you have an unstable reality that branches off, returning it would erase that new reality.

The time-traveler leaves a quantum trail when he/she moves in time and can be tracked to the new universe that was created due to the time-traveler's arrival.

Read the link i gave you for more info. all this info comes from that link btw. Anyway, I really, really hope this helped!! and have fun watching Endgame and Loki (Loki is my favorite Marvel show because I am a ultra geek for time travel lol) Bye for now!

-Boldbirds