Welcome to LQ! A good start is choosing a distro and installing it — have you done that yet? If you haven't, I suggest you start with Linux Mint. It's very beginner-friendly, has lots of users to help if you get into difficulties, is tolerant of most software, and doesn't have any features that seriously antagonise anyone.
You'll need to defrag and shrink your windows installation to free up space for Linux partitions. That's explained here
The program Gparted will be on the Mint installation medium.
Here's where you get an installation guide
and here's the place to download the installation image
You can put the image on a DVD or USB stick, as explained in the guide. Mint can then be run (rather slowly) from the installation medium, so you can try before you commit yourself to installing.