JT,
A pot
View attachment 45495in this configuration, has the wiper on the center terminal. This would be the lead with the arrow on your diagram. The other two terminals connect depending on how you want the turning of the shaft to effect the control. If it were a volume control for example, usually turning the shaft clockwise would decrease the resistance and increase the volume. If you wanted to reverse that effect you would reverse the connections to the outside terminals. Hope that helps.
Chuck