Oh my gosh! I know how overwhelming it is. Last year was my first year teaching and I had all these books in front of me and had no clue what to do with them.
I decided to sort out the books in groups that would somewhat
go together. All farm books together, all insect stories together, etc. Once I saw what groups developed I labeled a tub and put them in it. I ended up having several tubs. Some of the categories were, fiction fun, non-fiction, poems, nursury rhymes, math, favorite authors, series books (such as Athur, Clifford, Franklin), Dinosuars, and a tub for every month, which included holidays
in that month, or weather during that month. I left most of the tubs out all year, but exchanged the monthly tubs at a center in my room.