Adwords clarification needed

Yachts For Sale

Yachts For Sale
I have been looking at using adwords to promote a video I have just released, but am having difficulty getting my head around how it works.

Can somebody who uses adwords tell me: do I need to produce a separate video that advertises my channel in order to use adwords?

I ask because the video I want to promote is about 10 minutes long, so I can't imagine that youtube will insert it into somebody else's video in order to promote it. Maybe they insert a shorter promotional video that directs viewers to my channel when they click on it?

I'm pretty ignorant about this kind of thing...and to be honest I'm not picking it up very quickly either!