The structure

 Instead of using a wood plank and a shelve system from IKEA, I decided to go with a PVC tube frame. We have plenty of little hardware stores in Hong Kong, so sourcing the PVC tubes are easy and close to your home.
You can see on that picture that I have a clear white storage tank... that will help to develop algae :( Black is the way to go.

The only tools you need are a tape meter and a saw.

As the green tote is 42 x 30 x 10, the front bars are 40cm and they are made of 1/2" tubes... The side tubes are 26cm. Now I realised that I should have used 25mm tubes, as metric tubes are easier to source than imperial. 4 Ts per  shelf, 4 Ts for the base, and another set of 4 Ts for a link between the front and the back ladder to keep the structure together.

I found the PVC frame easier to modify and adapt to your needs. For exemple, I started with a single column, and then I thought that I needed an area to put my seedlings, then I added one shelf, and just cut the tubes of the existing frame, and put two T... Voilà !

You'll need tube caps for the feet. Elbows (L) are just for aesthetics...