that looks pretty easy to make..
2 20g totes, one much larger tote, prepare the two ones to be used as DWC units, easy enough, just follow any guide. then drill two holes in each tote, ideally on different sides, not side by side.
then get your bigger tote, this should be the same kidn of height as the smaller ones i guess, just longer, wider, drill two holes at bottom, as you've done for the 2 others. add nozzle things to each hole (garden hose adaptors will be fine) and silicone into holes. then attatch up all holes with hose, so that it's one big loop. large tote to tote 1 to tote 2 to large tote.
idea being that you fill it up with say 50g total, which will balance out across all 3 totes.as the water is used up it will lower across all three.
for one of the nozzles on the large tote, make sure that it's a male/male nozzle in that you can attatch hose to either side, inside and outside the tote. insuide the tote add a water pump, with it's inlet open to the big tote, and the outlet plugged into the nozzle. turn this on and it will pump water into tote 1 which will then add the excess water into tote 2 and such, all balancing out, that'll keep everything moving.
sohuldn't take more than an hour or 2