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.
Note: install the host OS on an USB stick with much space or an external hard drive. It should have at least 16GB, more than 64GB are not necessary.
As mentioned at the beginning, if you are not that tech-savvy you should use Ubuntu or Linux Mint. Just follow these and these instructions on how to install Ubuntu with Full Disk Encryption (FDE). If you want to use Linux Mint follow these instructions and choose the option “Encrypt the new Linux Mint installation for security” during the installation.
Tip: it is recommended to use an external SSD or at least a USB 3.0 stick.