Can someone explain to me how to figure out which Pokemon to breed for a Pokemon to know an egg move?

Question

So, yeah, like my question says, can someone explain to me how l can figure out which Pokemon to breed with to get an egg move for a certain Pokemon? I'm sorry if it sounds confusing, but, here's an example that was originally going to be my question, but l want to know how to do it in the future:

l wanted to breed a Deino (Hydreigon) to get an egg move Earth Power.
Who do l breed a female Deino with to get Earth Power, and how do l figure out what Pokemon to breed with next time so l know how to do it?

Thanks for your explanation, and my example is actually a question! ~

Answer 1

Well, To get an earth power deino, you have to breed with a Garchomp with Earth power, now onto the system.

The pokemon you want to learn the move, must have it in its list of egg moves, and be a female.

Then you have to breed it with a male , in its egg group, who knows the desired move.

In your case.

Deino needs to know Earth Power, and is a Female.
Garchomp has access to the move, and is in the same egg group, so getting a male garchomp with earth power, is your answer.

Also, In case you didn't know, garchomp learns earth power via move tutor.