First Place to start is What substrate do you want to use?
the PF Tek uses Vermiculite and Brown Rice flour (or sawdust and Brown rice flour) - this is the easiest method to learn how to grow mushrooms and many types work this way
Bulk runs need rye Grain or Wheat grain - you use your colonized rye or wheat grain to start off Bulk substrates like straw/horse poo and so on for giant flushes of mushrooms, or you can make cake tins filled with your rye or wheat grain with a vermiculite casing layer
Also, you can make Bulk bags using spawn / grow bags - Fill your bags up with Sawdust Enriched with Wheat Bran for growing oysters and shiitake very easily as you fruit start out of the bags - How to coming soon to growing info page, Ratios under the sawdust listing
Please contact us if you need any help learning to grow mushrooms :)