1 - If you have Plex Media Server installed on your PC and your NAS, then you have 2 servers. You only need one. If your PC can see the files on your NAS, then you can just have PMS on the PC. If you want the power saving of a NAS, then use only the one on the NAS and uninstall from the PC.
2 - If you want to watch using a Roku, the client is the Plex for Roku app. You install this from the Roku directly.
It only does this to authenticate your account. Once authenticated the connection stays within your network. You won’t see this again unless you sign out and need to re-authenticate.
