Garage Band tempos

I've found some old recordings of songs I made years ago, and I want to add drum loops in Garage Band to a track I recorded with an acoustic guitar, just to see how it sounds, and to experiment. So, I've imported the track into the timeline, but I'm wondering how I can adjust the tempo of the loops to exactly match the original track. It was recorded to a click, so it's already a precise tempo, but I can't figure out how to fine-tune the tempo to make them match up. Does anyone have any ideas?