Pokémon breeding is a method of obtaining a new Pokémon by producing and hatching an Egg. In the anime, it also refers to Pokémon grooming and caretaking.
First thing you will need to know when breeding is if the Pokemon are compatible, if you will.
There are groups known as egg groups, and Pokemon belong in certain egg groups. One Pokemon can be in more than just one egg group.
Why is this important? Only Pokemon in the same egg group can breed.
There are 16 egg groups, one of those consist of Pokemon who cannot breed at all(legendary Pokemon and baby Pokemon), it is called the undiscovered egg group. Most likely if you are trying to breed you won't pay much attention to this one.
Ditto just does not care about that and can breed with anything.
Pokemon can be bred by leaving two compatible Pokemon at the Pokemon Day Care center, located in specific location in every generation after generation 2.
If you know Ditto breeding, well then you know how breeding goes. It is exactly the same, after you leave two Pokemon in the day care center they will produce an egg and after a while it will hatch.
The Pokemon you get from the egg will always be the same species as the female parent.
There is something called "breeding rate", which tells you how likely you are to get an egg.
The time it takes for eggs to hatch depends on the Pokemon's species' required number of egg cycles. One egg cycle is 255 steps.
Here is a list of all Pokemon and how many cycles/steps are required for them to hatch.
That is the simple side of breeding, the more complex side of it is breeding for competitive Pokemon.
You have to watch out for IVs, inheriting natures, inheriting abilities and passing down moves.
PASSING DOWN MOVES:
- The baby Pokemon will start with any moves that it learns at level 1.
- If both parents know a move that the baby can learn by leveling up, the Pokemon will inherit that move.
- Before Generation VI, if the father knows any TM or HM that the baby is also capable of learning, it will be passed down.
- If either parent(before Generation VI only the father) knows an egg move that the baby can learn, it will be passed down.
You can check if any one of your parents has any perfect IVs in different cities throughout the games.
By default, the baby Pokemon will inherit 3 random IV stats from the parents. In generation VI you can give one of the parents the Destiny knot and it will pass down 5 random IVs instead of 3.
From Black 2 and White 2 onward if any of the parents is holding an Everstone it will pass down the nature without fail. If both are holding one it is random whose nature it will get.
In Generation VI, any Pokemon, including male and genderless Pokemon, can pass down their Hidden Ability when bred with Ditto.
If the male is bred with another Pokemon from the same egg group, Hidden Abilities will not be passed down.
Female Pokémon with Hidden Abilities have a 60% chance of passing on the Hidden Ability to their offspring when bred with a male Pokémon from the same Egg Group.
Sources: Lots of Bulbapedia and did lots of breeding as well
I hope I answered most of your questions because it took a while to write up, lol.
Anyways, hope I helped!