Have you read the FAQ? That should make it much more clear. You don't have to remember every thing there is to learn. Just remember what kind of move set competitive pokémon have so you can anticipate their attacks. You don't have to remember for example what type Ledian is, because no one in their right mind would use it. And of course, remember the (dual) types competitive pokémon have so you know the attack is effective or not. Like for example Zangoose. Zangoose's role is always sweeping and its move set is likely Return, Shadow Ball, Brick Break and Swords Dance, and occassionally Quick Attack/Flail. Other moves will make him worse, so even if your opponent gave it different moves you'll be at an advantage. You should know that you shouldn't bring Alakazam against Zangoose, since he'll get defeated easily by Shadow Ball.
I don't know if I should recommend this, so that's why I said read the FAQ first. And if you're not interested after reading it, then don't bother. Pokémon can get dull pretty fast if you don't enjoy it. That's why most people should just play it for fun and not worry about anything at all, since the game's AI is pretty easy to defeat. Stat enhancements? Don't need them. Fire Blast? Because it's cool. Ah, I should play that way too, it's much more relaxing than all the competitive battling. *Remembers the good old year 1997*