Mushroom science 101:
Take an existing mushroom, cut some tissue from the inside and place in a petri dish of agar (seaweed gelatin and food for the growing fungi). Leave until the dish is full of fluffy white fungi. Transfer to grain to let it grow some more, then straw and let the mushrooms, or fruit of the fungi, to grow. Add humidity along the way.
Overnight I got determined and went back to the course with renewed vigour. Some wonderfully detailed notes later as well as some practical experience and yes I can cultivate mushrooms from a tissue sample. See some of my other mushroom stories here.
So I got out my kit today, prepared my agar plates and let them cool. Then I took samples from my fresh oyster mushrooms.
Now I wait. I hope I achieved a suitable level of sterility so no foreign matter contaminates my dishes. I'll let you know when I get to the next stage.