As noted in the comments, the video/audio freeze out at the 15:50 mark. I uploaded a fresh copy of the video here: https://www.youtube.com/watch?v=g5cM60dH2-8
This is a walkthrough of the Alpha Dog vintage distortion circuit. I go through each section of the circuit and outline the principles of how each section works. Check out more DIY resources at https://www.vfepedals.com/diy