When looking at moves, you can break it down into a few basic parts:
Start Up - The time it takes before a move "comes out". Some moves are faster than others. Some have invincibility
Hit Box - The time where the move will connect with an opponent. Some moves have multiple hitboxes including sweet spots that give more damage and knockback and sourspots which do less.
Hit Lag - Freeze frames when a moves connects with an opponent. This is where you can "Smash Directional Influence" to move your character a distance each frame of lag
Cool Down - The time it takes before a character can move again. Some mores are faster in cooldown than others.
Make sure to come to the Teen Zone on Wednesdays at 3-4pm to learn Brawl tips and tricks