What's a good workout for a 16 year old boy? (any help appreciated!).

Okay so to be honest I’m not that strong and really skinny right now. My main goal is to bulk up and put on some muscle weight. I don’t have much equipment at home and it would be hard for me to go to the gym. I have a pair of 5 pound dumbbells but that’s about it (except this wierd seesaw thingy i have). Any help would be great thanks!