The numbers in the desktop license indicate the number of computers on which the purchased font will be installed. A license is required for all computers on which you plan to work with the selected font files.
If you are going to work alone and the installed font will only be needed for your device, one license is enough.
If several people work on a layout, and each of them needs access to font files, a license is purchased for several devices. If these are 2 computers, then 2, and so on. This can be any number: 3, 6, 10.
If you work with a font file, and then send the layout to a colleague who makes changes to the visual part without touching the font and without installing the font on their computer, they do not need an additional license.