Front panel is furnished painted on front. You are free to paint the back if you like, not necessary a good idea.
If your front panel is from a 3rd part manufacturer, you have to peel the laser film and clean the panel with acetone to remove dirt :
Then you sand the panel to help coatings to stick on the aluminium. Use at least 2 stages of primer and 2 coats of black paint for car.
Finally attach and titen M3 screws to the 11mm stand-offs :
You will sand (optional and only if you paint it) the enclosure and fold it on itself like origami. The assembly is done using rivets.
You need a piece of MDF of L x l x h or your hands only if you are as strong as Alpes Machines 😉
A mallet is used to perfectly mold the aluminium around the holes next to the edges.
Final stage : mold the enclosure by hand to get a nice shape.