>>717266669 (OP)
Fighting game fag here. You're not supposed to memorize the entire movelist unless you've been playing a character for months. Movelists in Tekken and SC are fucking huge, more so than any other fighting game. I play King in Tekken and he has 170 moves. Good players will use the same 25 moves 95% of the time, that's your "toolkit". The expanded move list beyond that is situational and expert shit.
What's your goal? Playing competitively in tournaments or just singleplayer?
If singleplayer, just mash, find what works, and enjoy the game. If you're getting your ass kicked by CPUs or just want to understand the game more, learn your character a bit.
If competitive, find SC2 learning resources and guide online.
To learn your character, you need to learn what their best moves are. Your best moves are your launchers and safe pokes.
The place to start is learning your launching moves and combos from them. Memorizing the combos so it becomes automatic muscle memory. That's free damage.
Alongside that, figure out what your best, safe, and fast moves are i.e. your "pokes". These are the moves you want to use 90% of the time since they're safe and low risk. You should have 10-20 pokes you want to know.
Launchers are high risk, high reward. Poke low risk, medium reward.
Learn what makes your character unique. If they're a stance character, learn what the stances do and when they're situationally useful. This will happen when you learn your pokes and launchers/combos.
After that, learn defense. You start to learn what other character's moves are and what's punishable (punishable = their move's frame data is so bad I can get a GUARANTEED attack after when I block it). Learn what's duckable and defensive options against strings (strings are ready-bake sequences of moves that are in the move list). For example, most launchers are punishable, that's what makes them high risk.
Also, to pick a character just pick someone who seems fun to you.