Need help building a box for my fi 18 btl

[sideway180sx 0]

need help with making a ported box for the 18 btl

i've measure the trunk space in the lincoln ls

Height = 14.5 inches

Depth = 24inches

width = 40 inches

also i will be using 3/4 inch mdf

so i just need to know how much i need to cut when i head out to home depot or lowes and what size to cut for the port

also what size screw should i use for the box? and material i should use.

this is my first box so be easy on me.