My suggestion is to get a book on building sheds. You can get the librarian to help you at your public library, get one at a book store, or look at Lowe’s or Home Depot. What you are looking for is one that shows building techniques. Pictures really help.
It’s good to see that you are not overwhelmed at the thought of doing it yourself. Once you know what to do and get a little practice it’s not all that difficult, but there are a lot of little things that can make it a lot easier. Things like drilling pilot holes to help start screws. And I do recommend you use screws. It’s a lot easier to take them out and fix a mistake.
Good luck with it and welcome to the adventure.