Log in with admin rights.
On the main page click on "Customize this Page"
On the block with the header click on the small gear wheel to edit it. It is just a box with some fancy html in it. You can delete or edit it.

Thanks a lot :)

Hello,
I've got a question about this block too. No probs with amendments of the content. My problem is the translation (language exchange). Where can I change the language so it appears in the appropriate language? Whatever I try, the content of that block appears (stays) always in the same language if I use the language switch at the top for changing. Could anyone give me a hint for that?

Thank you in advance.
Uli

We are aware of this inconvenience and will probably improve it in one of the upcoming updates. For now you cannot make widgets translated when you switch your site language.

Thanks for your answer. Pls put it on the to-do-list. Both "welcomes" (in standard installation) are widgets so it would make sense to make them translated.

Sure it will be added to the to-do-list.