Super easy. Plenty of you tube videos as well.
One thing to note that has not been stated yet. If your septic system wasn't installed with a garbage disposal in mind, it may be too small.
MKM also makes sunshades for different sized objectives. Personally, I don't want to buy good glass just to obscure the lense and block light transmission. I'd run a sunshade to keep light off the lense, but not worry about an ard
You can get honeycomb material off of ebay. Another inexpensive option is to just get a cheap butler creek flip cap and cut a + into the center of the cap.
Lots of videos and info online. Ultimate Reloader has his shop and some other areas built using conex containers. Very nice set-ups. Check that series out