The easiest way to rig the sail is to step the mast so the sail will hang vertically with the Center of Effort (CE) directly over the Center of Lateral Resistance (CLR which is usually the center of your lee/dagger/centerboard on a PDR.)

IMPORTANT: Remember the CE is measured from the luff (the leading edge of the sail) NOT the end of the boom.

You can use a traveler if you want - or just hold the mainsheet in your hand. Holding it in your hand is more fatiguing and less efficient, but it is very simple and cheap.