Simplest I can think of just now is to use “Merge Tempo from Tapping”. (Found under the Midi menu / Functions)
You would need to create another, percussion track (cowbell is ok), under the target / tempo track and tap along.
You will need the manual. It is quite simple but it did take me a couple of goes to get the hang of the settings and the idea of it. And it might take a few runs to get your tapping right but you can correct stray notes.
This creates a tempo pattern in the Tempo track and the “tap” track can be deleted. Everything else should follow suit after that is set up. Make sure that they’re all set to “musical” Timebase. You will see buttons in the Inspector which toggle a musical note or a clock. The clock is fixed timebase whereas the note state can follow the Tempo track. There are also boxes marked musical in the Pool for you Audio tracks to be also set to the same state. But that is for another time.
NB! The bass track may not work if the timing “spikes” (transients) are not sharp enough which is why I suggest a short, sharp sound like a cowbell.