Thank you very much,
1) I now found out how to get rid of the background image. Great! Good Video (but the music)
2) So, for Rocket Chat - there is now way to uninstall it. The same as the templates i do not use.
When i see them in the app manager - there is a Link to "Install" or to "Delete" - but once installed, the "Delete" Link disappaers. (??)
3) The language problem is that: I found lot of but translation to german - but wenn i search the original text - i have to switch every time. But that´s not the main problem. i can liv with that.
Thank you so much. I will study the tutorials - they are very helpful once they where found :-)
But one thing left: If i search the board here - everytime i go to an article the search is set back to zero. So i have to type in all again (or use many different new tab windows) - maybe that could be fixed.