You wish to upload your video onto youtube, and you need a simple melody or soundtrack to complement it, or simply make it less boring - Here is a great website jampacked with many types of music that you can use. Take care to read their terms carefully and comply - most creators require you to mention them in your credits at the end or beginning of the video: https://www.bensound.com/royalty-free-music/2
A very comprehensive set of lessons starting from the beginner to most advanced, with videos and text explanations. Free lessons with an option to buy various songbooks, DVD's, music theory books, etc.:
Another very complete website on learning to play the guitar - with a full range of lessons from beginner to advance. Very clearly illustrated explanatory videos. Either free or an option to take paid lessons.
Music Scores, Competitions, Listening
One of the most comprehensive sites for sheet music of all description. Both free music scores and for sale. Hear the music before you download. Competitions to take part in or simply help to vote for the winners: