For Mint, go to https://linuxmint.com/ , download one of the iso (f.e. mint cinnamon, 64 bit), burn on dvd or unzip the iso and copy the files to an usb-stick. Reboot, change in bios the boot-sequence to dvd or usb as first boot-device, insert dvd or usb-stick, reboot. On the boot-menu, choose now "Start linux mint". Now, the pre-installation-mint starts. You'll have an icon "install linux mint" now on the temporary desktop. Klick this icon, and the installation starts.