Are you talking about a simple chamber for PF cakes, or more like a monotub?
Both are similar, just get yourself a clear plastic tote. For the PF tek just drill a series of small like 3/8" holes all around the perimeter, no lower than say 3" off the bottom so if you over water your perlite you don't flood out the side. Open to fan and mist additionally as needed.
The other way in it's most basic form is the same idea. But take and use your drill and cut 2" holes around the perimeter, 1 on the narrow sides and 2-3 on the wide sides. This time maybe 6" up on center, allowing plenty of room for bulk substrate. Stuff with loosely bound polyfill, or better yet silicon glue on some patches of tyvek and have at it.
More advanced setups use simple plastic clothes tents or small garden greenhouses with a humidifier and all that hooked up to timers or to a rheostat, this time utilizing smaller trays on shelves.
Hopefully that answers your question.. It's been nearly a decade since I've grown and I'm just going off memory. You just need high humidity and plenty of FAE.