Google "plans for a raised bed" or something. It should come up with a lot.
The book is worth buying also.
I just bought some 2x12"s at HD, 3/4"plywood, and some 1x2"s to support the plywood bottom.
Some brackets and wood screws, your good to go.

Oh, just reread your post. You'r looking to build an elevated raised bed.
Hmm, I'm sure there will be plenty of good info and plans on google for that too.
Good luck

I used this link as a guide. It even has a breakdown of total cost. I used redwood and was able to build it for under the estimate provided.

Here is a link that might be useful: Raised Bed

To clarify, the Hero Garden is referred to:
http://www.squarefootgardening.com/WhatisHeroGardenBox.htm
I have googled raised beds and have not been successful in achieving one that meets Mel's SqFt plan, and I am committed to it, just overwhelmed and under-smart about carpentry, and I need good directions.

I don't have directions for one, but let me take a stab at making some up for your loved one.

First off, I think a 4x4 bed is the best you can hope for. If you build it wheelchair height, he still should be able to reach the middle from any side.

Start by byuying a half a sheet of plywood, which should be 4x4. Drill holes at minimum one hole per SF for drainage. Make them small so you don't lose too much soil. Then get 8 foot 2x6s cut in half and build a box and attach it to the plywood. For the legs, I think noched 4x4s are a good way to go, with the noch used to attach it to the bed. Cut the 4x4s long enough for ease of wheeling under.

I've never built one of these, but I don't think I've missed anything. Good luck!

Here is a link that might be useful: Sinfoian's garden adventure!

If you dont feel comfortable building legs for your SFG to stand on you can always go to a home store and buy sawhorses they are either plastic, wood, or metal and are both strong and affordable.

Have you considered writing to Mel's site to ask them?
Just a thought.

f you are a war veteran or know one of these Genuine Heroes who would be interested in receiving a standup or wheelchair Square Foot Garden Box, please contact the SFG Foundation write to info@SquareFootGardening.com or for more information visit www.SquareFootGardening.com. If you would like to donate a SFG Hero Garden Box Gift, the entire kit cost is $150.00.

More at -
http://www.squarefootgardening.com/PressReleaseHeroGarden.htm