Normal attacks are broken down into three basic types.
Light = 1
Medium = 2
Heavy = 3
Light attacks are weak but quick moves, usually used as combo starters or pokes. Medium attacks are slightly stronger. d + 2 are launcher uppercuts and anti-airs, while jumping medium attacks are usually crossup moves. Heavy attacks are slow but powerful. d + 3 is the universal sweep, while jumping heavy attacks are knockdown moves.
These moves are normals with an additional direction control. These are performed by adding back or forward before the button press. Some serve as low-attacks or overheads, which are very beneficial to the mix-up game of a certain character, and most are starters for normal combo attacks. The most notable of these though, are the b + 3 and f + 3 moves. f + 3 is an overhead which juggles the enemy and makes for a great juggle-starter. b + 3 is a wall-bounce attack which makes the enemy bounce to the other side of the wall and prepares you for another juggle opportunity. Both b + 3 and f + 3 can serve as armored moves by holding 3 while doing the move, then pressing the Meter Burn button while still holding 3. Finally, take note that you can cancel the MB version of f + 3 and b + 3 into a dash or backdash.