Q: how do I use a click track if the tempo changes in my song?
A: most sequencers can do tempo changes. but if you are actually just recording without a sequencer but you want to use a click, then you can still record your own custom click. Record yourself singing the tempo through the transitions, and then use them to calibrate the transitions, and line the clicks up to that. after having picked the tempos you want, and recording them both and then moving them into place. but it is much more likely that your sequencer can do tempo changes