The two mods are boxed in.  In the diode stage, you will notice there are two components to add in the space where the circuit board provides space for one (each diode polarity).  Just hold the resistor and diode together and twist the ends together and stick the other two free ends into the boar--solder.  then clip the twisted ends short and drop a glob of solder on top.  You'll have two components standing vertical side-by-side.   Do the same for the two series diodes.  Just make sure you have the diode directions correct in both cases.
			To hear a short audio sample of this, Click Here
				It isn't the most "unbiased" sample because it was recorded to demonstrate the "hawwah", so it is also processed by the Haw.  I will have some samples soon that demonstrate this circuit at its best, but until then, the above gives a short segment illustration of one sound it can produce.