To simplify: The Player’s Handbook has all the PokéMon Moves in detail and the PokéDex has all information on the PokéMon themselves: From habitat, height, weight, level-up moves, tm moves, tutor and egg moves, diet and movement abilities. Detailed abilities, such as invisibility, burrow, sky, land, etc. is in the beginning of the PokéDex.

Also: PokéMon aren’t limited to just 1 ability. They gain a second ability when they reach 25th level and gain access to their high ability at 40th level. You can hold off on your 2nd ability, however and just choose 2 high abilities at 40th level if you so wish and you can re-select your abilities when you evolve.

When you start the game, you start off as a LV0 PokéMon Trainer. You don’t gain experience like your PokéMon do but instead just gain levels whenever you do something that forwards your worth as a Trainer. Gaining badges, catching or viewing a certain number of PokéMon with your PokéDex, earning Ribbons or Trophies, defeating the Elite 4 or Frontier Brain, etc. each gives you a level. When you gain a level, you gain 1 stat point to put to your stats as a Trainer and gain a feature. If you meet the prerequisites for a particular class, you can become that class. This includes, but aren’t limited to, Psychic, Breeder, Martial Artist, Researcher, etc. Each of these classes have advanced classes beyond them that you can get into as well when you level if you meet their prerequisites. Some are: Move Tutor, Massage Therapist, Chaser, PokéBall Crafter, Weapon Master, Type Ace, etc. The level cap for a Trainer is 50 and the level cap for a PokéMon is 100. You can have a max of 3 classes as a Trainer until 25th level, where you may get 1 more class for a total of 4.