thank you. it's ok.

I can connect to ubuntu with the IP and my passeword in Winscp. not need a IP in Retropie.

The paths are specified in the docs - for the es_systems.cfg. For the themes, I think it's in the first post, but the idea is that the themes are copied in the /home/pi/.emulationstation/themes folder (which doesn't exist by default, you'll have to create it).