Save the file. It should be a .iso file. Then burn it to a CD. Don't just copy the .iso to a CD. It's a disk image. If you double-click on it that should open up your CD burner. If not, start up your CD program and find the selection that says something like "burn image" and do that. Next, reboot your system from the CD and make sure Mint runs okay and your hardware works, sound, network, etc and then you can install from the install icon. Once the installer starts just follow the prompts. I can't remember. Arer you planning on ditching Windows? If so, then let the installer use your whole disk. It's pretty simple, nothing to worry about. Post back here if you're not sure of something before you start!
Homemade Intel Dual-core 3.4 gHz, 4 gigs ram, EVGA GeForce GT 430
Mint 14, Arch Linux, Fedora 17