I use special bags from Umai:
https://umaidry.com/
It's pretty simple. Vacuum seal the meat in the bag, and let it sit in your frig with adequate circulation all around it, including underneath. The material of the bag has selective unidirectional permeability, so moisture leaves the meat and oxygen goes in. At 20 days, my meat had lost about 15% weight, at 40 days it was around 20%. That was consistent with what the website taught. The flavor gets deeper the longer you age. They say tenderizing is insignificant until after 20 days, and my 40 day steaks were much more tender than the 20 day. There is some waste, as the meat develops a hard, waxing skin that most people trim away.
My experience is limited to one 20 lb prime rib that I halved and bagged separately. One I cut one into steaks at 20 days, the other at 40 days. So far, I am a big fan of the process. I will do more.