https://www.youtube.com/watch?v=a848dIR8bQo
Set project tempo to beat tempo
Drag and drop sample
put it in timeline
RMB on sample
dialog box > time stretching > RMB on Time dial > Project tempo
To fix detuning:
dialog box > time stretching > Mode: Resample -> AUTO
Now when you change the tempo, dialog box will open up
Restretch all channels now?
YES
if you have existing samples, be careful