You show yours and I'll show mine
It really shouldn't be a terrarium as much as an enclosure. A terrarium implies a vivarium and what is most ideal for ball pythons in captivity is an enclosure where the ball python is the only living organism present. A vivarium also implies a glass fronted enclosure, most of which are not appropriate for keeping the proper conditions for a ball python.
Describe what you have so far... I think that will be the best way to see if you're doing it right. Pics are good, too.