Thank you Paul, I have spent hours, looking for an article about this module, which is nonexistent.
I did guess it is a timer, yet nothing happens, no matter how long you wait, DO is always LOW (or HIGH depending which jumper on the board is used). The POT is supposed to change the duration it takes for the switch to turn on (or off), in theory. The reason I am asking here is non of these theories are happening.
Now you learn to draw a schematic, using the data sheet picture of the chip and pins. Trace the board traces from each pin to the component where it ends, then add the component, resistor/capacitor, jumper or what.
From your schematic and the frequency selection table and the digital timer application schematic, you will learn how the thing is set up. It could be a single shot device to delay the starting of other devices when power is first applied, or could be a retriggerable timer, as when the master reset is pulsed.
I can't see all the silk screening on the board, so can't tell if there is an input connection somewhere. If there is no input connection, then the only possibility is a delay timer. Could be wrong about that.
In any case, you need to do the circuit schematic in order to clarify the board's use.