I have a greenhouse also. My husband mounts the shadecloth on the outside of the greenhouse. He has a huge long strip, drapes it over the center peak. The ends that are about half way to the bottom, he attaches a 1/2 inch pipe to each end hanging down, with rivets along the folded ends. The shadecloth usually lasts 2 years, and he leaves it on all year. We usually buy the sand colored cloth. The reason for the pipes attached to it is: it does not blow off when we have big winds, it stays put.
Darlene

It's customarily mounted on the outside of the g'house. I get shade cloth with grommets on them and attach haying twine to the grommets and down to the bolts on the kickboards.

We have all of our aluminet shade panels mounted on the INSIDE of the greenhouse. The panels have grommets and we use simple bolts to attach them to the inside tracks of our aluminum frame. We like it better on the inside since it doesn't interfere with our solar pool cover in winter (mounted on the outside), and we think it will last much longer on the inside. We also found it much easier to install inside.