Think I figured this out...
After downloading dev tools 1.3beta
open each folder till you find the DevTools folder
upload THAT folder(
only that folder) to
public_html>extensions
Then I can see it in All Extensions
click install (little arrow)
Turn it on
Go to System> Should see Dev Tools
Go to Design>Templates
Click the double page icon(bottom right on the Default picture)
follow instructions on screen
I didn't notice an option for cloning Bootstrap5...maybe someone else knows??
I have one more question:
Why download all those folders if we don't need to upload them?