Right: To use KStars/Ekos on Windows you need an INDI server attached to your equipment (for example by plugging USB cables into it). Also the INDI server has to be reachable on your network (for example via WiFi or hard-wired ethernet).
The idea is to plug the mount, imaging camera, guide camera, focuser, filter wheel etc into a cheap ($45) RaspPi out by the scope, and run everything on Ekos from your windows laptop either indoors or out by the scope.
Personally I MUCH prefer this to sticking a $1000 laptop outside in the weather. It does take some getting used to and setting up. But the convenience of separating the user interface form the wires is just fantastic.
You've certainly come to the right place to get advice!
Right, it seems you answered your question quite well
It's a Server-Client architecture. KStars is the client, where INDI is the server. INDI is what communicates with the mount. It can be running on another computer or raspberry pi or whatever. You can then use a client (e.g. KStars) on Windows/MacOS/Linux to remotely connect to the server. Seems most folks prefer to run the server on raspberry pi since it's relatively cheap and small.