If you are a fan of the avengers you have to watch all the films of the Marvel Cinematic Universe (MCU). To do this, you must check an Avengers movie order.
Captain America: The First Avenger (takes place during WWII)
Captain Marvel (takes place in 1995)
Iron Man (takes place in 2010)
Iron Man 2 (takes place after Iron Man)
The Incredible Hulk (time unspecified, pre-Avengers)
Thor (takes place six months before Avengers)
The Avengers (takes place in 2012)
Iron Man 3 (takes place six months after The Avengers)