You need to beat the first gym and teach a Pokemon Rock Smash(Machop, Bidoof or main Pokemon and then you talk to a rugged rock and it will say "Would you like to smash it?" choose YES and, POOF, it's gone.
Chat with our AI personalities
HM06 Rock Smash
EASY. GET ROCK SMASH!
You use HM6 Rock Smash.Which you get in jubilife city in the cave after you get the poketch
use rock smash on the rugged rock and the guy will give it to you when you smash one of the rocks
well first of all one of your Pokemon need to know the hm rock smash then you press a twice while touching the rugged rock