bud drying cabinet

Whats up, Just wondering about my bud drying cabby.
I've looked around on the internet for DIYs, and only found one that had no details.
There are some on here but seem to dry way to fast.
Now I have a 20 cubic foot cabbinet with no bottom for fresh air to come through. Does anybody know if a need a exaust fan, or just a circulating fan
Thanks

I just use a cardboard box. run wire to hang bud. after hanging the bud I close it up and then open it for about an hour a day. No fans or air just a box. takes 3-7 days to dry enough to go into jars,

Well I didn't by the cabbinet I just found it in the trash and extended the back of it. I was think about either hanging string on through it, or just lay levels of chicken wire from side to side.