I`v just updated my game and was able to create my own prison but it didn`t say you could down load other prisons any where

If someone uploads the map somewhere else, you ought to be able to download it and play it:
https://www.reddit.com/r/theescapists/comments/2xnisd/banks_facility_custom_escapists_map/
The issue is that most people use Steam Workshop and don't upload anywhere else.