Installing the host OS
To be able to run Whonix, you must first choose and install the host OS, on which you will later run Whonix. Like a program that you run on an OS, only that the program in this case is a full OS itself.
As mentioned at the beginning, if you are not that tech-savvy you should use Manjaro, Debian, or Linux Mint. Just follow these instructions for Debian, or these for manjaro and these When installing make sure you are fully encrypting your device or you’re not securing your host OS! To do this make sure you select “Guided - use entire disk and set up encrypted LVM” while setting up your operating system.
Tip: it is recommended to use an external SSD or at least a USB 3.0 stick.
It is also important to remember you will need to update your host, and the software in it manually yourself. If you do not do this periodically you could be leaving yourself open to vulnerabilities.