Select the color you want and click on a District on the map. Right-click on it to remove its color or hide it.
Search for the District (Kreise/Landkreise) you want and click COLOR SUBDIVISION to fill it with the current Fill Color. To remove the color of the selected District, choose REMOVE COLOR .
Add the title you want for the chart's legend and choose a label for each color. Change the color for all districts in a group by clicking on it.