Cast Iron insert fitting

[Alleyrabbit]

Hi, i have recently bought a second hand cast iron insert and gas fire. it's a stovax like The Cecilia Victorian 54" Package but i can't work out to fasten it to the wall and we don't have the surround. it came without any fixings and i can't see anything on the back that would show how it should be fixed.

so can anybody tell me how i fix it to the wall?

Many thanks Ali