Practice pages 6 and 7 on bells. Remember to pay attention to the music, being careful to play flat notes when you see them. Also, if you see a key signature at the beginning of the piece, remember to flat all the notes that are flatted in the key signature!
Also, practice exercises number 22 and 21 on snare. Notes with the "z" in the stem mean you need to buzz the note. Don’t feel discouraged if it’s hard! Keep working on it and it will come!