Every year some poor bugger who has probably never done it before it gets to rig the tarps and be responsible for any soggy miserable nights that might result if it's not done well enough. Starting from the bare space it's really quite hard to know where to start if you've not done it before, so this doc attempts to provide some advice.
Note that this was written after Wookey+Joe's rigging effort in 2014. It is not necessarily optimum, but did seem to more-or-less work. Feel free to imporve it over time.
There are two essentially-separate jobs:
If there is any chance of it raining soon, start with the water tarp, as you really don't want to miss it, and setting up in the rain is rubbish.
I will describe things as if standing at the bottom entrance looking up, because that works for all three sections. So the left wall is the gear/stove/animal-hole wall. The 'back' is the top end of the bridge. The 'front' is the main entrance.
This is one large tarp covering more than half of the internal roof. There are two main cross-ropes to hold it up, ties at the back edge and 'knitting' to reduce sagging in the almost-flat central area. The objective is to get it taut enough and square enough that almost all the water runs down the top and out the front not collecting in 'buckets', which then drip. That means that it has to be fitted quite 'flat'.
Start with the big green 10x10m tarp. It seems to be near-enough square so don't worry which way round you start. The basic position is that it goes all the way to the right wall, partly 'underneath', and the left hand edge is about in line with the steps up the middle. The back edge lines up with where the roof rises at the back entrance.
Start by rigging
So start by opening it out to full width on the wide central bed-shelf. and pulling the RH edge