Here it’s how to choose and change the root of your treen the sosa 1 :

• ·         Open your genealogy
  

• Click on the settings icon (on the top right next to the printer).
• Click on Settings.
  

• ·         Click on the person you want to modify on the source individual (sosa 1)

• Enter at least one name to select the desired person
• Click ont the Save button

On the same screen, you can also choose to show sosa 1 when you open your tree. 

To go further

You have an article on the sosa numbers and theirs functions in the family trees : identify correctly your ancestors in a tree.