This is a harder question than you think. I may need some more information about what you have.
Are the books written for a Trumpet in treble clef or are they in treble clef sounding as written (piano, violin, etc.)?
Are you familiar with trombone as a transposing treble clef instrument? I.e., are you a Brass Bander?
If you play trombone in transposing treble clef, you need to move the regular treble clef notes up a whole step. If you see a C, you should play your D:

should be read/played as
If you play trombone in bass clef and can read clefs, transposing treble clef parts can be read as tenor clef.
If you want to read regular treble clef music, you probably want to read down an octave:

is played as
I hope I haven't confused you any. Try to explain better where you are and where you want to go and maybe I can be more helpful.