Think of it like this, there are three pieces to this ecosystem, Indilib, Ekos, Kstars. Indilib handles anything to do with physical hardware, mounts, cameras, etc. Ekos is at its heart, controller/monitor of this hardware. Its the piece that lets you deal with focus, guiding, aligning, and scheduling. Kstars is really just planetarium software. Its a little more complicated than this because Ekos is integrated into Kstars and not a separate piece of software that you can run independently, but logicically they are very distinct in function.
I'm sure I'm oversimplifying this but hopefully this helps.