writer- tools- mail merge wizzard - 3.

Hello!
In writer - tools - mail merge wizzard - 3. Insert address block - 1. Select different address list:

I have options “edit” and “change table” inactivated (grey).
Version 4.0

Please, what do I have to do to activate those options?
If I choose and mark blue the line left (datotheke name sheet name) I still do not get anything…any other suggestions?

MANY THANKS!!!