How did Tony knows when to go back to the 1950s to get back the Tesseract? Could it be he read his dad's files or...?

I understand that timeline for these comics is like multiple universe. But... something still bugging me.

So, is Cap back to the history to kill him self and replace to the old Cap so that he can with Peggy or what?
Or he just let the old him trapped inside the ice in deep ocean and future him go to date with Peggy?

Clearly there will be 2 cap when he back in time.

Can someone tell me what's the logic behind?

The most common theory is that Cap went back to 1940's to be with Peggy and created a new timeline. His old self at the end is just him traveling from this alternate timeline.
How can he travel to our timeline when the time already synced up? Remember he still has the GPS coordinate from when he was supposed to return.

i'm curious about this too. the dialogue is spoken by the wrong tony?

Same reason why does Thanos have limbs similar to humans, fingers, hands, head, body & butt 😂😂😂 questions won’t end

I remembered how Capt America accused Tony Stark in the first Avenger that he is a hero pretender who only fights for himself and here we have at the end, Tony Stark gave up everything, literally everything, he was the biggest loser among all of them and he gave it up. Just whoa. Well done Marvel Studios. Well done.

Yes it’s been theorize that there is 2 cap,

And this Steve Rogers went back in time, marries Peggy Carter, and fathered 2 children.

Remember in Captain America Winter Soldier, Cap visited old bed ridden Peggy but She (Peggy Carter) has amnesia.

Her husband was also ’unamed’ in that movie. So the theories of possibilities. Perhaps that Steve Roger just let other Rogers continue the Captain America thingy and this future Roger just went back explained some things to Peggy (but not all maybe of the events) & married his dream gal

The events of the rest continues, when present Steve Rogers return back in time to place the stones as if it didn’t disappear.

We have seen 2 captain America can coexist in one world (without causing a time paradox or whatever)

That dialogue was Tony Stark (endgame Tony) in the special unit uniform telling ant man/Scott Lang describing to him who the central characters are when the Iron Man tony (2012) Stark & Steve Rogers were being approached by Alexander Pierce (Robert Redford) & his crew at the lobby

It wasn’t the 2012 tony stark/iron man narrating the assasination attempt on Fury. Don’t be mistaken.

It was super confusing because of the close shot. May need to pay attention again when watching the 3rd time.