1st time scrog screen, HELP.

Hey guys, I'm planning on using 2 plants in a scorg screen under a 400 watt hps in a 4x2 grow tent. I was on wondering what kind of materials would
I need to get started for the scrog. and how far should I put it up? thanks.

I built my screen out of free parts https://www.rollitup.org/blogs/blog22374-my-1st-scrog-screen-build.html someone told me to keep it about 12"-24" above growing pots, but I also think it has to do with your veg time.