Chapter 12 deals with actions, but this is probably the relevant section:
§12.9. Check, carry out, report
The normal behaviour of an action is specified by its three associated rulebooks - check, carry out and report. In the case of our “photographing” example, these rulebooks will be:
Check photographing. Here, for instance, we need to verify that the player has the camera. If any of our checks fail, we should say why and stop the action. If they succeed, we say nothing.
Carry out photographing. At this stage no further checking is needed (or allowed): the action now definitively takes place. At this point we might, for instance, deduct one from the number of exposures left on the film in the camera, or award the player points for capturing something interesting for posterity. But we should say nothing.
Report photographing. At this stage no further activity is needed (or allowed): whatever effect the action had, it has happened and is now over. All we can do is to say what has taken place.
It may be easy to forget that carry out rules can still have if/else statements or apply to specific situations, such as “Carry out attacking someone with a melee weapon…” “Carry out attacking someone with a ranged weapon…” which will all be considered after all the check rules pass.