I'm assuming you have some kind of substrate i.e. paper towels, newspaper, ect. Corns love to burrow and aspen bedding works well for that. The water dish should be large enough that your snake can fit its entire body into. I'm also assuming that your undertank heater is on one side of the tank so there is a warm side and a cool side. You'll also need at least 2 hides, one on the warm side and one on the cool side. These can be anything from small empty boxes to deli cups turned upside down with a hole cut for entrance. A humidity cage would be great, but arent required. I'm sure somebody else will had more to this....
I dont want to sound like a jerk, but a little more research prior to buying your snake couldnt hurt.
How big is your snake? Post some pics, I'd love to see him/her! Good luck, and enjoy your new friend!
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**Am I the only one that gets frustrated when I cant find just plain old white paper towels?? I dont want any dorky lookin flowers in my snake or dragon cages! Its the little things in life that bother me....**
1.1 Bearded Dragons - Chong & Cheech
0.1 Anery Motley Corn - Fluffy
0.2 Labradors - Booger, Maggie
0.1 Cat - Hardcore