If you buy heavy galvanized hardware designed for farm buildings for your shed, it’s overkill. Buy heavy-duty closet door hardware instead. It’s not really meant for outdoor use, but when it’s protected by an overhang, it holds up well. And if the roller bearings get corroded, it’s simple to replace the entire hanger mechanism. Check out Johnson Hardware’s 111 track and 1025 ball-bearing hangers.
You can build the walls on any flat surface, but the shed platform is ideal. Snap chalk lines on the plywood deck, 3-1/2 in. from the edges of the platform, to indicate the inside edge of the walls. Measure to make sure the lines are parallel and 89 in. apart. Then chalk a line down the center (Photo 1). You’ll use this line to make sure the angled top plates meet in the center.