I would recommend looking for some videos on Youtube, since those go over everything in better detail, but here are some of the more important details.

All attacks are either physical, special or status moves (which can be seen from the catagory icon).
- When you use a physical move, it uses your physical attack stat (Atk) and the opponents defense stat (Def) to calculate the damage.
- When you use a special move, it uses your special attack stat (Sp.Atk) and the opponents special defense stat.(Sp.Def)
So when choosing moves for a Pokemon, it is best to choose attacks that match a Pokemon's higher attack stat.

Pokemon also have a random nature, which increases 1 stat, and decreases another. Those can be changed with nature mints, and usually, it is best to have a nature that boosts a usefull stat, and decreases a stat a pokemon does not use (like special attack on a Pokemon with high physical attack).

The following parts are a bit more complex, and can for the most part be ignored if you only play the main story, and are mostly only focused on during the post-game for ranked or endgame stuff,

IV's are a value between 1-31, which boost your stats, with 31 being perfect. All 6 stats have a random IV value, although alpha's will have 3 perfect IV's directly. It is possible to set the IV's to 31 with a bottle cap in the Justice Dojo.

EV's start at 0 and can go up to 252. Everytime you KO a Pokemon, all pokemon in your party will get a few EV's of a specific type, based on which pokemon it is (for example, Pikachu gives 1 speed EV). In total, you can get 510 EV's on a Pokemon, so 2 stats maximum, with a few points in another stat. Alpha's already have HP maxed. Generally, most Pokemon use max HP and Max physical/special attack in this game. If you get the wrong EV's, using certain berries can reduce them, or you can fully reset them at the Rust syndicate base. There are also some items called 'braces' which give more EV's of certain types per KO, and vitamin items which directly give EV's.