What does 1 and 0 mean on this power supply?
If you are referring to the two dials, they are used to set the voltage - hence the label "Set Voltage".

At a rough guess you select the voltage you want from the sum of the two dials. The left dial gives you even voltages (multiples of two), and then use the right dial to achieve odd numbers.

For example 9V would be selecting the "8" on the left dial, and "1" on the right dial, to give you 8+1=9V. You can select 4V by selecting "4" on the left dial, and "0" on the right dial giving 4+0=4V.

You can confirm or reject this assumption by testing the power supplies.