What is the best way to add a variable tempo to my project?

My project contains recorded audio, audio loops, and midi notes.
I’d love to make it just a little more human, by adding a variable tempo.

My question is: how does one go about doing this with so much data?
I mean, if it were only midi then there wouldn’t be much of a problem, but how do I get all the audio tracks to stay in sync with the new tempo?

Set the clips to musical mode

Hi Svennilenni,

Thanks, but does this need to happen before, or after the tempo changing?

Before