Thermostat Reptile

I have been looking on the internet for snake racks and i have found one that i like i just don't understand how to buy it. I think i have to buy the tubs separate from the rack. And i know i would have to buy them a heat source and a thermostat for them but i don't understand what they mean with there way of ordering. But for the heat source couldn't i use the heat lamps i use already.
I have posted the site i am using could u guys look at it and tell me what they mean about the things i don't understand.

http://www.freedombreeder.com/reptile-racks/large-frame-racks/fb-large-racks-cb70.html