The work plan was not confirmed with the Floorman to ensure he understood his responsibilities, particularly the requirement to use fall protection while RIH. Although he had completed Work-at-Height training, it was overlooked that he had not performed Derrickman duties for over a month. The lanyard was available and in good condition, but the Floorman failed to inspect or attach it as required. The Driller discussed preparations with the Assistant Driller, but did not verify that the Floorman on the Monkey Board had his fall protection lanyard attached. An experienced Floorman was substituting for the Derrickman, but there was poor communication between the Driller and the Derrickman to confirm the lanyard was secured. During the Toolbox Talk, there was only a general discussion about working at height, the team was advised to wear safety shoes and use fall arrestors, but no specific verification occurred. the Driller lacked adequate supervision during operations on the Monkey Board. No designated person was assigned during the Toolbox Talk to monitor or assist the Driller in confirming that the Floorman was wearing his lanyard, nor was it confirmed that the Floorman fully understood his duties on the Monkey Board. The Floorman failed to connect his safety lanyard, and no crew member intervened to stop the unsafe act.