For your convenience we've made our own assembly video, which will guide you step by step how and where to put each piece on the board and put it all together. Also it will show you how to test it and get EMG data.
https://drive.google.com/file/d/1n6Dkdjhp4RhXZi3RyhXSAcAtEkWE_joQ/view?usp=sharing
For a print version of the assembly guide you can check out DIY Handout guide with part description, below.
https://backyardbrains.com/products/files/MuscleSpikerBox.v.1.4.BuildingInstructions.pdf