Suggestion. Take a break, then come back and double check everything you've done so far. Then, read over the instructions to get some familiarity with what is coming up. Then slowly, do one step at a time and verify each step is correct before going to the next one. This will help your quality control, and minimize the chance of hidden errors that will show up later.
There should be no pressure to get any of this done within any time frame. That will only make things harder to deal with.
Go to the web and review the process that's out there regarding the build of the M125. There is a good narrative about this along with helpful pictures that will give you an idea of how to run wires and place parts.
I built my M125 amps over a period of about two or three months. I must have checked every step three or sometimes more times. At the end of it, I had two amps that were identical in build and of very high quality. Both functioned perfectly from the first startup, and are working well now, about a year or so later.
Lastly, your soldering will determine how well these amps work. Spend proper time doing that. If you feel irritated, mark your spot on the instruction sheet and walk away until you feel like you want to do more again.
Good luck and enjoy the process!