I've never been quite so stuck on a byoc build (they are so well put together), but here I am.
I populated the board and all offboard components, as described in the build doc, to the point of testing as described in Keith's video. However, this was halted at the first stage of plugging in to a power supply (I was using a 200mA 9v supply), as no LEDs lit up. I did a little poking and prodding of the LEDs to no avail, switched the loop/preset switch, then fired up my dmm to start checking voltages.
I should note that I am somewhat embarrassed to say that once a circuit starts putting actual components in my path I am woefully lacking in knowledge of how to trace, read and interpret voltage readings.
After checking that I was getting power to the board I noticed it smelled hot, then stupidly touched the heatsink to... we will say "confirm."
At this point I unplugged and began looking for mistakes and obvious visual signs of bridged solder joints etc.
I am hesitant to plug the power source back in, and now feel stuck. My next move is to post this and reflow joints. After that I'm not sure what to do given my hesitance to power up without guidance.
Edit: apologies for the link to photos. This is the best I can do at the moment.
https://photos.app.goo.gl/g8D5Z8zxBy0NH9ZF2