An eighth note triplet is a group of three evenly spaced notes played within one beat. Eighth note triplets are indicated by three eighth notes grouped together by a bracket (or a curved line) and the numeral 3. The eighth note triplets are played with one third of a beat each. Triplets are easy to understand once you have heard them played. Listen to example 46 on the recording to hear the effect of triplets.
Once you are confident counting triplets, try moving them around between the snare drum and the toms. Use alternate sticking beginning with the right hand and then reverse them.
Now try this one which uses triplets on the bass drum (right foot) and snare drum (left hand) while the right hand plays each beat on the hi-hats. This one is tricky, so take it slowly at first.