If the job has to be done fast, I use the quick method.
Manifolds on first
Twin turbos with y pipe and oil drain tubes already attached
no intake pipes on either side
a flexible racheting 14 wrench takes care of the 3 nuts on either side of the turbo inlets
To get the rear intake pipe on (the hardest part), I stick the gasket on the intake pipe with some adhesive, and install the pipe with the bolts already in it.
I remove the abs line heat shield to gain more access. With the intake pipe in place, I start the bolts on the rear intake. It is a very awkward position, arm snaked all the way under the turbos and back up. However, it works for me and I can work the bolts on. Then a racheting 12mm wrench to tighten them. The rest is obvious from there.
Some people take off the turbos and leave the drain pipes on the engine. I'm sure it works fine, but I'm pretty sure my way goes faster and helps prevent possible oil leaks at the gasket.
I know it is hard to visualize, but hopefully that will help.