You're not dumb. If you want to see prime examples of truly dumb questions, you can browse through threads I have started.
One of the best things you can do with a new-to-you boat (and actually kind of fun in a way) is to open up all the hatches and start tracing all the plumbing you can find. You will answer questions that you don't even know you have and gain a better understanding of the boat.
As you do it, take some blue tape and a sharpie and start to label things as you discover what they are. You can get fancy with the labeling later. I can spend and hour tracing a hose and figuring out where it goes and what it does only to come back a couple days later and not remember what it was. Hence the blue tape and sharpie.