You just can't use copyrighted music really. It will save you a lot of hassle to just search up Non Copyrighted music. Be careful with games as well. Microsoft doesn't let just anyone monetize content from their games. Blizzard lets you use any of the content and monetize your videos with no problems (As long as it isn't offensive such as racism, porn, etc.) I think Steam is the same as Blizzard when it comes to their games. I'm pretty sure Nintendo is strict with who publishes videos with their games as well.