manifold vaccum for vaccum advance ?'s

so how do i perform a leak down test? i have alot of tools. i probably have every tool i would need to do this. I dont know a whole lot because if i ever had any issue like this my old man would take over and fix whatever it is. But i wanna learn how to do this kinda stuff myself. So if somone would like to walk thru on how to do a compression test and a leak down test i'd really appriciate it.