I had my first success growing shrooms using the PF tek over 20 years ago, pre-internet. There was a PF tek booklet about 20 pages long sold by Robert McPherson. It was advertised in high times.
https://en.m.wikipedia.org/wiki/PF_Tek
I would go that route if trying to learn, or buy pre-sterilized substrate.
http://www.en.psilosophy.info/pdf/psilocybe_fanaticus_tek_(psilosophy.info).pdf