The size of the board makes it easy to measure what's going on inside the circuit. Just connect the probes from an oscilloscope to any of the solder or test points on the board.
A photo of the board that I built is below. I also wired a sample test circuit for blinking a pink LED and then connected a scope to the board so that I could look at the square wave.
Here is the sample test circuit that is wired on the breadboard. Substitute resistor and capacitor values where applicable.