IMPORTANT! Beginning with this step, do NOT fully tighten the bolts you install. You'll see why later.
It might be time to grab a helper if available, but you can do it alone if you're careful. The vertical frame support attaches to the lower frame using two large bolts. Slide the bolts in from the top, then add a washer and a nut to the bottom. Tighten them almost all the way to the top, leaving a little wiggle room in the assembly.
