I have autism too and I've also struggled learning competitive. here's what i know, albiet it's very beginning and not an all size fits all ruleset. I hope it helps you get started though:
- look at moveset threads for the pokemon. look at moves and read why they're picked
- for pokemon with strong attack stat, they usually have strong, 100% accurate, attacking moves
- if a pokemon has high special attack, they often use strong, 100% accurate, special moves
- pokemon with high hp and defenses usually have status moves to set up or inflict a status condition.
- for pokemon that have a high attacking stat and a high defensing stat, it's usually a 50/50 in the movesets between status or attacking
- use a nature that boosts its highest stat and weakens the weakest stat.
- give an item + ability that will enhance what you're trying to achieve in your moveset
the best way to learn is to battle, watch battles, and read why people select the moves they do. take a look at our moveset threads. you're welcome to ask questions here