|"i have downloaded the iso file and installed it to a disk"|
Just to be clear...you didn't simply copy the ISO file to a disc, you used a burning program such as ImgBurn to convert it & burn to a disc, right?
If you created the disc correctly, all you have to do is boot off it & run Linux directly off the CD. If you like it, then you can install it. Like clive_pearce said, many Linux distros have an installation icon on the desktop. Just click it & it will walk you thru setting up & formating the partitions. You should have at least 2...one for the file system & one for the swap file. Many recommend adding a 3rd partition for user files.
Which version of Linux do you plan on installing?