Install it. Go through the process of making a basic board. Very basic. Just to teach yourself the KiCAD way of addressing schematics, netlists, component mapping, PCB layout, etc.
When you get stuck, search on YouTube for a specific helpful video. (Chris Gammell [Contextual Electronics] has made many, but there are others as well.) Consider following Chris's "Getting to Blinky" series, which I think was last updated for KiCAD 4, so it's not a perfect match, but it's a good starting point.
I went from having a little bit of Eagle experience many years ago, but never using KiCAD to having a completed simple board design for a Nano, a battery, some APA102 LED chains, a remote control sensor, and a few sockets in the span of an evening. Boards worked first spin as well. I started with the Blinky video series, even though I was using KiCAD 5.
https://www.youtube.com/playlist?list=PLy2022BX6Eso532xqrUxDT1u2p4VVsg-qThe KiCon conference also just happened and there are a lot of videos from that that might be helpful as well.