Are you asking what is the most used features in solidworks sheet metal? I would say for me after base flange or convert to sheet metal, that the list would look like this, Edge flange, Hem, Vent, and Miter. However I work in the sign industry and I am sure every industry is different.
First, sketch on the face and select the vent option and get going!
this link should help you https://www.youtube.com/results?search_query=vent+in+solidworksd