There is a cool DIY retro computer kit, but the official tutorial/guide is in a dozen or so videos, approximately 1 hour each. No text equivalent IIRC.

Halfway through the first video, the presenter says "and to debug, you would need this clock board" (which is another kit). At least you can half-ass it, which is what I did. Then in video 4 or 5, you need a chip programmer (TBF i think there was a note that you might need it, but still is full stop otherwise). Kind of half-assed that one too, but still...

IMO videos are a great presentation media, but are horrible as tutorials.