I didn't watch the whole thing, but I assume he is "lapping" the valve seat.
This works if you have a leaking valve and the seat has been scratched or similar and you have an all metal seat and needle, often times needles now have a neoprene tip on them to make them seat perfectly.
But anyway, this isn't your problem, a leaking needle valve causes the bowl to overflow and floods the engine
when it's excessive, your is sticking closed, or sounds like it is.
If there is someone around that can show you how or maybe even pay them to let you watch, just tell them you don't mind paying, but since your a cruiser, you really need to know how to do this yourself, your paying for a class.
Most mechanics will be flattered and understand your not trying to keep from paying next time, your just not likely to be around mechanics and need to know how to do this yourself.
It's really a simple procedure, but trying to explain it on the internet
is I guess like trying to write a procedure to teach someone how to tie their shoe, exceedingly easy to do, but I could never explain it, but could show you easily.
I wouldn't bother glueing on fuel
lines either by the way.
If there is a way you watch while someone cleans your carb, it would answer 1000 questions