Thanks Ewan. That node seems to add more depth to my list of indexes rather than less.
So I’m trying to use the “Surface.ByPerimeterPoints” node to generate the surface and I get a “Points are coincident” error. I’m basically trying to do exactly what is in this thread : Get windows and door coordination and I’m stuck at the part where the guy says " OK, now I have a closed polycurve." I can’t get that polycurve or anything resembling it.