I have two Books:
Bookcases by Niall Barrett and Woodsmith's Bookcases, Shelves & Cabinets.
Both contain some simple plans and are probably available at the library.
Basically, you could just use 3/4" plywood [which won't be quite 3/4"]
Cut sides to length (height) and depth
Cut shelves to length and depth
Cut dados in sides for shelves
Cut rebate in sides for back
Dry fit test assemble, tweak as necessary, then do the actual glue up.
Clamp and allow to dry.