Welcome to MR, gram.
Everyone feels confused when they first start. There is even a whole forum about "Which one should I buy" right here..
https://www.mobileread.com/forums/forumdisplay.php?f=123
I guess the first thing to figure out is what type of books do you read the most? NYT best sellers, romance, science fiction, classics? Do you want to be able to borrow library books? (We have lots of free ebooks right here on this site.)
Knowing this will help in choosing the type of reader that would work best with your reading habits
You have already given us a clue that you would like something simple to use as you are a novice to computers. If you give us some more information we can offer some suggestions.