It is very simple. Kits are available everywhere; either an oak log soaked in spores or a small kit - spores and growing medium. At the moment we are using coffee grounds as our medium. They are free for us (thanks to the Spanish drinking a lot of coffee) and they provide enough nutrients thru the cycle so you do not have to add any additional nutrients - even after we squeeze them for the oil & when finished with the growth we then turn them into fire logs ( the coffee grounds). You can also use sawdust or wood chippings - not from a chain saw.
As long as you can replicate mother nature in a small portion of your house you will be fine. Temperature, humidity, and light are all important. A Fluorescent or LED light is fine - mushrooms do not get a lot of light on the forest floor.
Kits are available online for around 20€. Our kits are shiitake and king oyster - the easiest to grow with good harvest numbers.
Happy Gardening..
spore syringes