Ok... I understand, docker is like VirtualBox o WMare (emulation virtual system). Docker under Libreelec is LinuxServer.io under Libreelec addon repository (whale symbol). I must install this addon and with docker management gui called Portainer (http://<ip>:<port>) I can import Docker images for Librelec.. it's right?
From Portainer gui I can download docker plex image with this command : "docker pull linuxserver/plex"Tonight I try to install Docker addon and download plex docker image...
To configure Plex I confused...docker commands example are very strange.
There is an add-on for Plex already. You should use that one. The add-on settings let you configure everything automatically. No need to do it manually via portainer.
You can use portainer to manage things we don't have an add-on for.
Also, read this: LinuxServer.io docker addons and general docker info