I'm a newbie too but here's what I think...
First off congratulations! You''re definitely at the right place. The people here are very nice and many are extremely knowledgable herpers. Second, I strongly want to encourage you to pickup a book or two. They're fun to read and will get you started in the right direction. The Corn Snake Manual is considered the golden Corn Bible and thus comes highly recommended. Here is a list:
The Cornsnake Manual (Bill and Kathy Love)
Corn Snakes: Reptile Keeper's Guide (Bartlett, Richard D)
Corn Snakes and Other Rat Snakes (Complete Pet Owner's Manual)
As for the cage setup Russsss is correct, you're going to need a warm side and a cool side (regardless of whether or not it's a hatchling). Corns enjoy about the same comfort zone as us humans (70 deg F. on the cool end to around 80-85 F. on the warm). Some like it warmer than others. Being reptiles (ectothermic) they have to regulate their own body temp by moving from cool to warm areas. I use the Exo-Terra under tank heaters for our snakes but others are available. Be sure you get the right size heater for your tank. I would get a couple of temperature strips too. Place them inside the tank near the floor- one on the cool end and one on the warm. Again, temperature is very important to maintain a healthy corn. Don't use heat rocks or you might burn the poor fella's belly.
I believe that UV fluorescent lighting is considered optional. I've never read anything that supports it to be of benefit (I could be wrong though), but it does make the viv look much nicer.
Hides are very important. Most Corns are secretive little buggers and like to hide from us. Make sure the hides aren't too large if you get a hatchling, Corns like to cozy up in tight spaces. Place one hide on the warn side and one on the cool side. My hides have some plastic plants on them that my snakes seem to enjoy. Also it gives them another place to rest and regulate their body temp.
Corns need a constant supply of water. You will need a good sturdy water dish to prevent it from being spilled. If the air is dry where you live then you might want to consider a fairly wide bowl. A larger surface area of water will aid to increase humidity. The water is usually placed on the cool end of the viv but it can be moved closer to the warmer end to increase humidity as well. Be sure and clean the water bowl regularly, and not just add water when it's low. This will help keep your snake healthy too.
I use repti-bark for my bedding. If you choose some form of wood chips be sure it's safe for Corns- definitely NOT pine (another reason to read the Corn Snake Manual). Pine and other woods can cause respiratory infections. If money is an issue you can use newspaper. I use repti-bark so my corns can burrow. It's fun for them and fun to watch. I don't recommend reptile carpet, it holds oders and is a pain to clean.
Lastly, make sure your tank is secure. If your Corn can get it's head out his body will follow.
I Hope this helps. Good luck!
Cheers,
Jason