Prologues are often just a section of back story or setup. The best advise on prologues is, don’t do them. Don’t write prologues to sneak in back story. You shouldn’t need to! As you work on your writing skills, you will learn to quickly and effectively weave the back story into your writing.
Don’t do them unless it is in a book in an established series. In that case, it brings the reader up to speed for the current story. Usually a short recap of where the protagonist was when the previous book ended or any major shift that happened offstage.
An epilogues is a piece of writing at the end of a work of literature, usually used to bring closure to the work. Situations may call for an epilogue if the denouement differs from the main narrative in time, place or narrative style.
Unfortunately, they are also not recommended. They are usually attempts to fix an unsatisfactory ending. Are they sometimes acceptable? Sure, if you write one to tie up loose ends. But if you are writing it to answer questions not answered by the “real” ending, then you might want to consider re-writing your Act III. Too often, they are written to make sure the reader “gets” the ending. Your story should speak clearly on its own.