Do you mean, how do I use Rock Smash in HT, or how does the movement work?
I'm going to assume the latter, so here's how I did it, it's pretty simple:
To put a rock smash in any script, you'll need this:
How this works, is the applymovement makes the rock move through a series of frames (you can look at or edit them in OWEditor RE), to look like it's breaking apart. Then hidesprite kicks in, hiding the rock, and since you're not setting a flag, the hidesprite isn't permanent, so the rock will reappear after you leave the map.
If you want the script to be useable for all smashable rocks (for instance, I use the same script for all of my rocks, to give the player an extra smashing option), just make sure each rock has a unique PersonID, and instead of the hex value after applymovement or hidesprite, put LASTTALKED.
Does that answer your question?