Adding user created content?

I’m pretty new to this and curious about adding user created content. I loaded someones file that included keys and bass. Do I have to have a midi keyboard/synth hooked up to play the non-drum parts? Are there any videos available explaining this? I also downloaded a file that contained all of Abbey Road Side two, and half of the drums are missing, but it looks like I can move them around individually in BBM. Are there any tutorials explaining this?
Thanks a bunch!

To use files with keys and bass, you need to download and install the drumkit that the songs require. These will generally be found in the User Generated Content - Drum Sets section. No midi keyboard is required. The sounds are in the drum kit. Yes, bass and keys are in a drum kit.

Thank you!