I'm guessing it has UEFI? If so that is going to be a lot of fun trying to get to the BIOS...You have to go through about 5+ random hops through the Win 8 metro garbage to get it to restart into the BIOS. I don't remember them all, but I think this is how is works: Go to the right edge, and click something like PC settings, that will take you into a metro screen. from there I remember that Win 8 and Win 8.1 were different here, but for Win 8 it was then something like general, and then something like advanced restart, and then I think you had to select change UEFI settings. I think you have to make a back up of Win by going to something like backup and restore from the control panel, but I'm not sure. You will need a large USB for it as the Win 8 backup files are over 16 GB if I remember correctly.
If you are sure you want Linux, I would avoid all the Windows hassle and return that computer and get a nice powerful desktop from system76
. They come with Ubuntu pre installed, so they are made for Linux. You should be able to run Mint on one of those very easily. That's just my choice though, and I thought you might be interested in it.