if youre talking REALLY BASIC BASICS, here's some tips.
most basic comboes go from weak to strong, in a chain. Most of the time to make things easy, do it while youre crouching, so A, B, to C. (example. A, A, A, B, C). Later on you'll learn what everyone calls your BnB (Bread-and-Butter) which is your primary combo for dishing out damage.
Practically all characters have a "launcher", it's a ground hit that knocks them into the air. You chase them down by tapping Up, on your d-pad. From there you can follow up with another combo same way you did from the ground.
LEARN TO BLOCK PROPERLY. I personally think this is more important than learning combos. This is something you just can't get from playing the computer, you gotta go to the arcade and play against real people. Basics- people coming from the air, you block high. dash-ins from the ground you block low. If you're knocked down, statistically you should favor blocking low, unless your opponent is tricky.
LEARN TO IDENTIFY WHEN TO ATTACK. You generally attack from a neutral vantage by dashing in from the air, or from the ground. If you're on the defense blocking an attack, recognize gaps in your opponent's attack so you can get away safely. Then start over again.