How to attach a box to the wall

[trasker]

I am going to build a soundproof box to place over the fan unit for our mechanically ventilated floor to reduce the whooshing noise a bit.

The fan is mounted on a concrete wall partially below and partially above ground.

I plan to build the box in MDF and insulate it inside.

What is the best way to attach it to the wall? I could mount two hooks on the concrete wall and two loops on the box, but that felt a bit too simple

 

[-RB-]

Could a french cleat be something perhaps?
https://www.google.com/search?q=fre...msung-gs-rev1&sourceid=chrome-mobile&ie=UTF-8

 

[trasker]

Could a french cleat be something perhaps?
[link]

Exactly! Thank you, I couldn't quite understand what I needed, but that's it!