I sat and stared at your video for a while, I realized I had this problem once......
make sure you get the flywheel on correctly. You don't want that to cause a problem later on...
Also make sure your woodruff key isn't all sheared up because this could cause your flywheel to not seat correctly. Replace that if need be.
get that flywheel fixed so it is out of the equation.
As for your clutch problem........
It is not your clutch pads slipping on the bell housing, but your clutch is more than likely slipping on the crank's axle.
Simple fix: torque it on more
so, now you gotta DO THIS:
pull your spark plug and put in a piston stop.
If you don't have one then you can use some rope.
If you use rope make sure your piston is past your ports so you don't get the rope stuck.
You gotta do this so you will be able to apply to correctly apply torque.
Fuck draining your oil.
Go to a place where you can lay your bike at a 45 degree angle.
Now you can take the clutch cover off (and the oil won't come out).
I used to do this when I was fine dialing my clutch (saves so much time).
Now get your socket, and tighten that clutch nut up.
When I had this problem, I was using a Top Racing Crank, and I really had to torque it on there. . . you might be in the same park / might not.
put it back together.
start it up, and then go ripping.
If it is still slipping, you might not have torqued it enough.
Timing and carb issues.....
If you have points, do it by the book.
If you have cdi, do it by the wiki.
Fix your air leaks please....
Carb tuning somewhat can depend on what carb you have....