Hey, I will make this quick and clear:

If I were to want to upload a mod that has audio from sites such as YouTube, would I have to ask the original uploader and credit as long as it's not copyrighted, or use it and credit the original author? I'm still relatively new to this whole copyright mess as it's a bit troublesome to understand it. I don't even know where to get most of the sounds or music too.

Thanks in advance.