To embed Youtube videos, just put the YT code (the jumble of letters at the end of the URL) in the youtube tag. Core admin: you should put instructions in the post comment page.
A screen grab seems to show a milled slot with back filling (adhesive). The length of the threads on the “inside” isn’t consistent with a dowel screw (usually the same length (although it could certainly have been shortened)).
But as Julius suggests, the dowel screw would certainly be the most economical way to do this (by far).