WordPress Basics: Adding video
This video is an overview of how to work with You Tube videos for newcomers. It is a fairly recent video so the steps here will be helpful to you if you are not familiar with embedding. Incidentally, the videos you are seeing on this site all follow the same embedding process shown. It is about 10 minutes long and shows some tips and methods to embed and size your videos properly. It also points out the need to keep within the rights framework before publishing.
I have found several free sources like this and hope it will be useful to those just starting out.