Once I had a rough idea of the diameter of the trunk, I put up hooks on the ceiling and let them stand for a bit. The trunk was then secured by the loops on the hooks. Went very quickly, and the fabric and soaker hose weren't very heavy, so it went up easily.
I cut the fabric just as it touched the ground. Ideally, I would leave some and make twisting roots. But we have cats, and they would take laying fabric as an invitation to...yeah. So aesthetic ceded to practicality. Made it lighter on the hooks, and easier to vacuum/carpet clean--which I still need to do...at some point.
Next I mapped out the leaves. I took a bunch of hooks and the piece of (crocheted chain) yarn I was to use to hold up the 'branches' and made a slightly larger circle around the trunk.
I slid all of the branches onto the yarn, then slid a couple between each hook point. Here it is half done:
And all the way around the tree