TL;DR:
Make sure to finish the server setup through its local IP address. If you’re working on the Windows machine hosting your new server, open http://127.0.0.1:32400/web in your browser. If it’s on a different machine inside your home network, use http://[PMS IP address]:32400/web instead.
After you’ve finished the setup (e.g. named your server, linked it to your Plex account) you get the option to create your first libraries. You’ll now also be able to see/access the new server through other Plex apps.
Give users a little more than 2 hours to react.
Keep in mind it’s the weekend.