There are so many ways to tell a story. You can start at the beginning and make sure the reader know everything that’s going on. You can have a point of view character who learns things as an excuse to teach the reader what is going on. You can do it all as a flashback or memoir and have a different frame for everything.
Or you can just throw all of that out the window and trust that your audience understands the conventions of the genre you’re in and can fill in a lot of the blanks for themselves.