Continuity is making sure there is a connection between 2 points. Usually on a multimeter when the 2 test points have continuity, it will emit a beep. Forward voltage is a way to make sure the diode itself is ok. If black probe on band side and red on the other lead of the diode, you should read a number which represents the voltage drop. If zero, or infinity, the diode is bad. But that aside, let’s try and tackle one thing at a time. Try jumping the octave section and see what you get. If you still have nothing, please open a thread in the troubleshooting section so we can get more eyes on it. One thing I will tell you is that for the most efficient troubleshooting please do a visual inspection including verifying all the right parts are in the right place, look for any solder joints that may need a reflow, check for solder bridges, and clean the solder side of the board with isopropyl alcohol and a toothbrush to remove any excess flux. Once you have done all that, post some good, well lit photos of both sides of the board and all jack and switch wiring. We will get you there.