Don’t ride on public roads until after you’ve taken the BRC. Practice starting and getting it moving in a parking lot just to get good with the clutch but THAT IS IT.
There were people who failed the BRC course I was in because they had never operated a motorcycle style clutch/shift system before (and contrary to popular belief driving stick doesn’t prepare you for it) and didn’t get it down by the end of the first day of riding. Practice with that and THAT ALONE. That is it.