The short version is put the disk the drive, boot to the disk, and follow the instructions. The explanations are very clear.
For those who've never installed an OS, it can seem to be mysterious, but it isn't. You pick a target drive, create a partition, format it, and tell the installation to proceed. Somewhere along the way the install routine will ask for some information, such as language to use, time zone, logon password, and the like; answer the questions, and, when instructed to, reboot.
Linux distros know they may be installed by persons who have never installed an OS before. Most of them have tried to make to process as easy and transparent as they can.
k3lt01's links will help explain the process in detail and should answer any question you have.