how hard is it to do a wall in a 91 explorer?

i had a wall in my 92 explorer.it was a 2-door.i had 4-15's in a wall.the box went from top to bottom and side to side.i removed the back seats.it wasn't to bad.just take measurement from all sides and when building the box,leave some room to play with so you can get the box in the truck and in the upright position.

heres some pics of it before i covered it in vinyl.i had air bags on it,so thats what the floor is cut out for in the back.