First off, a refresher on GM moves: there are two types, soft and hard.
A soft one is a GM move where the consequences are revocable or pending. That usually means that the player is in a spot that they can get out of, and maybe that if they don't get out of it there's something bad coming. Some examples: getting trapped in a net, the goblins start their charge, the rumble as the temple starts to collapse.
A hard move is a GM move where the consequences are immediate and more or less permanent. Damage is the typical example, but there are others: the duke cuts off your funding, the ground collapses and you fall into a deeper level of the dungeon.
The text mentions three times to make a move: when everyone looks at you to find out what happens, when the players fail a roll, and when they give you a golden opportunity.
When the players look at you to find out what happens you make a soft move. Remember that not every move is entirely bad: maybe you reveal an unfortunate truth, or tell them the requirements and ask.
When the players fail a roll you make a hard move. Damage is often an obvious choice, but there are more: the goblin dodges your swing, nabs your coinpurse from your belt, and runs off with it. The ogre pins you under one meaty hand.
The the players give you a golden opportunity you can make as hard a move as you like. Doing nothing in the face of an onslaught is certainly a golden opportunity, as is doing something amazingly dangerous without precautions: walking up to a troll, insulting its ancestors, and slapping it on the face (all without a weapon or armor). This is kind of the "if they ask for it" rule. It's often a good idea to clarify that's really what they meant to do first. "So you're really crossing the profane circle on the floor to interrupt the ritual? The one that just turned a poor goblin to dust?"
So you're making moves all the time, really. In fact a lot of what you already do as an experienced GM (which I'm presuming you are) could be counted as moves. The 6- result is just a cue to make that move as hard as is appropriate to the situation. The rest of the time you're making softer moves, unless they really set themselves up, then you go as hard as you like.