netrunner 14 new install

i have downloaded Netrunner 14 on to a USB stick, how do i re-install? do i un-install 13.12 and if so how? should i do a backup of data first and how do i do this sorry to be so ‘dumb’ but i am very new to netrunner
thanks again for your help

You don’t need to uninstall or re-install, there is an update script you can run in a terminal, here is the link:

Yes you should always perform a backup of your home directory before an upgrade.