Evening brother!
Sounds great, post some pics when you do!
Before you start check out monotubs and how to grow in them, on youtube.
They can be made in various sizes,so to fit your closet.
You'll also need to paint the inside with waterproof paint, so you can bleach wash it to keep it sterile, no old exposed wood!
Carpets are the enemy of the mushroom grower, the harbor tons on spores and bacteria etc which can easily cause contamination.
A hard washable floor is best in the closet grow area, if possible.
Hygiene is paramount for success, you will need bleach and
isopropanol alcohol id decent amounts, always be cleaning.
I'll say no more, check out youtube, there's tons of good info!