How do you get Dragonite to learn Roost?

Question

In Bulbapedia, it says Dragonite learns it at the Start.
l'm not sure what that means but can someone explain?

Answer 1

One easy way is to give it the TM. But since something else will probably like that better, just go to the old Move Relearner in Blackthorn and give him a Heart Scale. Roost is available there.

Answer 2

That means that Dragonite can learn Roost at LV 1, so to teach it, you have to use a Heart Scale on it. Hope this helps...