The Mesh is made from 2mm galvanised steel.
The supports are made from stainless steel.
Fix the special joist support around the flue making sure the grooves are pointing upward.
Place 2 of the mesh panels into the groves.
Now using the fixings (provided) bolt the other 2 panels together to form a square around the flue.
Now slide the second joist support down the flue with the grooves point downward, until the mesh panels go into the grooves.
Now tighten the special support.