My solo technique is to set the ring on a temporary support so it rests level and stable at the correct height. I actually made a dedicated support to do just that. It looks like an old hat rack with a horizontal cross of 1x4s at the top that support ring. Just get that rig set in the center of the yur. t
However that support is long gone. Now I merely balance the ring atop an 8' step ladder. Tricky because it can tip.
My yurt wall is just over 5'. If your yurt wall is low, like 4', you can 'freehand' erect the ring with three rafters. Get the rafters appropriately stacked around the yurt in a vertical position so you can grab them as needed. Insert two into the ring in third section with the outside of the rafter on its lath cross. Install the third rafter into the ring, raise the third after and ring until you can set the third rafter on its lath cross. Never done it seen it done on:
camping yurts you tube set up