Go to Lilycove City.
The Move Deleter in Pokemon Ruby will help Pokemon forget learned moves, including HMs which cannot be forgotten any other way. The Move Deleter lives in a house east of the Lilycove Department Store.
you can get rock smash from a house in mauville city, the house is directly right of the pokemart
I think its the city beneath the trick masters house
On the move deleter house at the top right on lilycove city
At littleroot town its the left or right house.
After defeating the third Gym leader
go to the trick house there you can find blitz
you don't find a beldum in Pokemon ruby. you can get one in Stevens house where the 7 gym leader is. its in the top left house. you find a pokeball and it has a letter from Steven. BTW i think you should finish the pokempn league before you go to his house.
you need to go to mount ember and move team rocket to move out of the way somehow
Use the move dive to go underwater to find shards in the seaweed.
In Verdanturf, in a house. A lady with a Pikachu.
In Pokémon Ruby Sapphire and Emerald versions, HM7 contains the move waterfall. You can find the HM in the Cave of Origin.