Cut the shelf and side pieces to size. Drill 3/4" pocket holes at both ends of each shelf piece. Attach the two shelf pieces to one side piece with 1 1/4" pocket hole screws and wood glue. The front of the shelves should be flush with the side pieces with a 1/4" gap on the back.
Cut the toe kick piece to size and drill 3/4” pocket holes at both ends and one side. Attach it to the side piece, against the bottom shelf, with 1 1/4” pocket hole screws and wood glue.
Attach the second side piece to the shelves and toe kick piece with 1 1/4" pocket hole screws and wood glue.
Cut the back support piece to size and drill 3/4" pocket holes on both ends. Attach it to the back of the side pieces, according to the diagram, with 1 1/4" pocket hole screws and wood glue.