The GM, dice, and moves
In Stonetop, the GM doesn't normally roll dice and they don't trigger moves. If you're fighting a monster, the GM might declare, "It leaps at you, claws out and hissing." But they don't trigger Clash and they don't roll dice to see if the monster's attack succeeds. Instead, they ask, "What do you do?"
If you ignore the leaping monster, then the GM will confirm that you understand the situation and really want to do that. If you do, they'll tell you what bad thing happens as a result.
More likely, you'll do something about this monster leaping at your face: you duck and hope it flies over you, or twist away and stab it, or raise your shield to block it. This will probably trigger a move, and the result of that move will inform whether or not the monster's attack lands.
For more details, see the Running the Game chapter Running the Game. For more on fights specifically, see Running combat.