Greetings & Welcome @OppZ!
I’m not saying this is absolutely correct, but I normally wrap the top, bottom, & sides with an extra couple of inches of foam board insulation. The back side is going to require a large cut out with an opening grill covering it. You can probably salvage one from a wrecking yard.
Then it’s just a matter of building a cabinet around it. I build the cabinets with 3" of clearance on the top, bottom, & sides. Not because it’s needed today, but because if it ever needs to be replaced with one of slightly different dimensions, it’ll still fit without having to rebuild everything.
Cheers!
"Be the reason someone smiles today!" ~ Van_Dweller