In my shop there is a small area I share with other tenants with some food storage and a fridge and microwave, so I decided to close it off to keep the dust out and add a bunch of wall and loft storage space.
The frame is all 2x4 construction, fastened together with 3" deck screws (because I had an excess on hand). It was fastened to the walls with 3" deck screws and to the floor with concrete anchors in a powder actuated gun. The french cleat panels were used in my last apartment for storage and I moved them with me to my new place, but the fit perfectly in my shop. The door was salvaged from my grandparents house when I built them a newer, beefier door. Enjoy!
I start out by padding the existing exterior wall so I have a flat surface where my new wall will attach. I also attach a stud directly to the wall which is where my newly constructed wall will join with the existing wall.
I measured out from the wall and marked on the floor where my new walls would go. A line is drawn at both of the new walls to align the sill plate on the floor.