To calculate the capacitance of a long, thin metal strip with width 2a and infinitesimal thickness, one must consider the relationship between surface charge and potential. The capacitance can be derived from the geometry of the strip and the electric field it generates. The discussion emphasizes the need to understand where the electric field is stored and how terminals are connected. It highlights that a metal strip can function similarly to a capacitor, with charge proportional to potential. The user seeks guidance on determining the capacitance to facilitate potential calculations around the strip.