Instructions
Catch a Pokemon that can learn Ancient Power, such as Omanyte or Yanma. For the purposes of breeding, you want to catch a male Pokemon that knows Ancient Power. To determine the gender of the Pokemon, look for the male insignia next to the Pokemon's name. If it is a male, capture it; if not, let it go.
Train the Pokemon until it reaches the level where it can learn Ancient Power. For example, Omanyte learns the move at level 37, while Yanma learns the move at level 33. To train a Pokemon, use it in Pokemon battles to obtain experience points.
Catch a female Pokemon that is compatible with the male Pokemon. Mating compatibility is based on egg type. For example, Omanyte is a Water Egg type, so it can mate with other Water Egg types, such as Krabby or Wooper.
Fly to Solaceon Town and visit the Pokemon Daycare. Leave the two Pokemon that you want to mate with the caretaker and leave. After walking around a certain number of steps, your Pokemon will produce an egg, and after more steps, the egg will hatch.
Return to the Daycare Center after the egg has hatched. If the mating was successful, you will have a baby Pokemon that knows Ancient Power from birth.