Endgame 1. Ant-Man talks about time traveling

After avengers lost a battle against Thanos and Thanos made a snap which takes half of living form into dust. During this time , Ant-Man was in quantum realm . Since during the Time of Thanos snap ,The machine got stuck . After then ,mouse comes in same Van And Ant-Man again came back from Quantum realm . He found something strange . Then ,he knew about  Thanos snap.

Ant-Man has only spent 5 hours inside the quantum realm and in outside world ,it was already 5 years. Captain America , Ironman and hulk has already started a new life. Then he went his home and met his daughter which was already older as 5 years . Then he went to meet  captain America and tells him about quantum mechanics and about time travel concept . There captain America ,along With Black widow also thinks of thia good idea and they ran for Ironman . Ironman Denies to group again together as he was busy in family matter. So they went to Hulk place as Hulk was also smart enough. He accepted the proposal and started building Time machine. But because of something bug in his codes it was not working properly . But in next seen ,we see Ironman was also making Time machine and which was working properly. Since the Time machine is already fine and superb working they went for collecting stone From the past and want to made their own snap so that all life form that were snapped can be restored again.