This is probably an easy question for most of you.
I drew this image with pens and scanned it; I want the background to be black, everything that's not the drawing, you know, like the people are lying on top of outer space or something and it's showing through their hair All the tutorials I have been able to find are just for black and white images.
I am pretty much a Photoshop beginner, using CC 2017, so if you choose to answer this question probably best to write like you're talking to a beginner. Thanks. Seriously, thanks <3