Start the video then just click on the “G,C,E or A” buttons to hear the sound your strings should be tuned to. The G string is the one closest to your chin when holding the TUB-Uke in playing position – the A string is nearest your knees.
How to make a simplified TUB-Uke
There are instructions for making a simplified version of the Tub-uke in Nick Penny’s book Making Musical Instruments from Junk.
You can buy a copy of Making Musical Instruments from Junk from Nick Penny’s website.