Hello, Covana
Flam is a staccato-like hit on the snare drum, usually used in marches, but also used widely as a "fill" in pop music.
A "drag" is a hit on the snare that is a bit behind the intended beat. I.E if you are to hit the snare on the 2 & 4 , you still would in theory, but you would stretch it a bit further.
Kind of hard to explain, but easy to show you.