Boom Line Set Up?
Ok, I'll give it a shot.
The line running across the stern of the boat is called the traveller. The "boom line" is called the main sheet. You want the main sheet to go from the pulley on the traveller, up to the aft end of the boom, along the bottom of the boom, and then to a cam cleat probably located on the cockpit floor to secure it. Rig that pulley so it can slide along the traveller.