Reishi (Ganoderma lucidum) are one of the most studied of all the medicinal mushrooms and is known as the mushroom of imortality.
It is quiet easy to grow but It takes a much longer time (2-3 months) to fully colonise  the hardwood sawdust block compared to Oyster or Lions Mane, and also takes a much longer time to put out the mature mushroom ready for harvest (1-2 months)

 The grow bag itself can be used as its own  humid dome grow environment. SO DO NOT OPEN THE BAG
It will grow as thin antlers inside bag and will grow towards the top of bag, once it gets near the top of bag then you can open/ cut the bag slightly, and  when exposed to the higher oxygen levels, the mushroom will begin to grow thicker.

Once ready, harvest and made medicinal tea and/or tinctures. Kits may be grown indoors, and may also be fruited outdoors during the spring and fall.

Watch this a video posted on youtube of someone growing out a Reishi kit.
https://www.youtube.com/watch?v=ywGOiZRE5Yw

and please view other instructions from other sites and sources such as this one
https://northspore.com/products/grow-your-own-reishi