If you’re going to be serious about playing the bassoon, reading tenor clef is a requirement.
If you’re unfamiliar with it, click through to Mike Spark’s website for a quick primer.
If you could use a little practice reading the notes, try eMusicTheory.com’s C-clef trainer. Click on “Settings…,” choose “Tenor clef,” and click “OK,” then click “Start Drill.”
The next step, of course, is to get your fingers to do their thing automatically as you read the tenor clef notes. Try Oubradous for a gentle introduction, then move on to the Milde “Studies in All Keys” Op. 24 (also found in this edition of the Weissenborn method) for a more serious workout.