Welcome to the Apple Support Communities, and congratulations on the new MacBook! You have not messed anything up and are on the right track. The next step is to install Snow Leopard using the Snow Leopard Installation Disc.
You can find the steps to install Snow Leopard to the new 1 TB hard drive in the following article. You will need to format the drive to Mac OS Extended (Journaled) using the steps in Part One of the following article and then follow the rest of the article to install Snow Leopard:
Once you have Snow Leopard installed, you will need to run all of your software updates, and then install Mountain Lion from the purchased section of the Mac App Store. Steps 3-6 in the following article outline how to reinstall Mountain Lion after you have already purchased it:
Finally, you can restore your Time Machine backup to the system using Migration Assistant. I recommend following the steps in the section titled "Time Machine or other disk migration" in the following article:
Thank you for using Apple Support Communities.