you are able to use the move rock smash but first you have to find the HM you get it from a chbby boy on route 36,35, or 34 I hope this helped?
beat the 6th gym leader and you will be able to use it out of battle. teach a Pokemon that is conpatiple with hm4 like machop
The first HM that you are able to use outside of battle is the Cut HM. You get it from talking to the captain in the S.S. Anne.
To teach a Lapras how to swim you first need to find the hm Surf. Surf is located in the Sarafi Zone at the top of Fuschia City. However, you are not able to use the hm until you beat Koga, the Fuschia City gym leader.
defog is the third usable hm after you beat fantina, the hearthome gym leader.
You use HM's just like you would with TM's, you click A on it and select use, then you select a pokemon who you wish it to learn the HM, then once it learns it you will be able to use that move outside of battle and inside of battle. TM's are one use only and should be used with caution. HM's have an infinite amount of uses, but cannot easily be forgotten, as they can only be forgotten by the Move Deleter
beat the 6th gym leader and you will be able to use it out of battle. teach a Pokemon that is conpatiple with hm4 like machop
U get The HM move CUT in Rustboro city ...but u will be able to use it only after u beat Rustboro's gym leader 'Roxanne'....
Defog
surf
Yo ave to beat the gym in order to be able to use that HM, then after acheiving said HM and teaching it to one of your POKE MANZ, you can just click on rock and move that mother trucker
First you have to beat Team Rocket in Mahogany Town and Lance will give you the HM Whirlpool. You also have to beat the Mahogany gym to be able to use it.
fly
Teach a move to a Pokemon that can learn it via HM and then, after defeating Falkner in Violet City, select that Pokemon in your party and select Flash to light up dark caves, such as Dark Tunnel.
u get to use certain HM's once u beat the gym leaders
You need to get the HM dive from Steven in Mossdeep City. Then you will have to beat the gym leader in Mossdeep City. Then you will be able to use the HM dive. And you find the dark spots in water while surfing. Use dive. And to resurface. Use dive again!
hm defog
The hm it self is in Mossdeep, but you have to beat the gym to use it outside of battle.