KiCad's Central Project Manager window
When designing PCBs with KiCad, you use a number of different programs.
There is "one ring to rule them all"… the Central Project Manager.
It is what launches when you invoke KiCad. Once you have established a project, you can go into it via its .pro file. You can also go from "place to place" within KiCad, e.g. start CVpcb after doing what you do in eeSchema, without constantly returning to the central project manager… but is it still a useful part of the system.
You need it to start a new project.