Mounting pod to A pillar.

Hey all, I tried to search but came up with nothing so here's my question... I understand how to construct the speaker pod itself, but how do I mount the pod to the desired location?(i.e A pillar, doors etc.) Or maybe I'm completely off thinking that the pod can be made then mounted. I'm just wondering what the best way to attatch the finished pod. Thanks for any input.

screw it on?

screw it on?

So just take the A pillar off and screw it on from the bottom? Sorry if I'm overthinking a simple solution, just want to make sure I have my plan of attack in order. Thanks for the quick reply.