Question

before beginning maintenance, the operator must shut down the engine and then: clean the floor around the equipment collect all of the tools and equipment they will need tell everyone in the area not to use the equipment attach a do not operate tag to the starter switch

Explanation:

When performing maintenance, to prevent accidental start - up of the equipment, attaching a "DO NOT OPERATE" tag to the starter switch is a standard safety procedure. Cleaning the floor, collecting tools, and telling others not to use the equipment are important but not the most crucial step right after shutting down the engine for preventing accidental operation.

Answer:

attach a DO NOT OPERATE tag to the starter switch