Generic brand drill has no instructions because boys are born with drills?

OK maybe the instructions are lost. Or maybe I shouldn'e say there are no instructions just because there are no pictures om the instructions. I have to ask each time how to insert and remove the drill bits. Have I been drilling in reverse? Not that I noticed. I drilled for this first time this week in a maple log to insert Pleurotus pulmonarius (Phoenix oyster) plugs. I had to use a rubber mallet to pound them in but they did not all go in completely because I was drilling at an angle in a narrow space on a log that should not have been mounted to the fence first. I won't be on site to see if the mushrooms grow in six months but I guess I can check the website.