Multiple names for one person
Maybe for a person you want a name with a nickname between quotation marks, such as
Herbert “Herb” Powell
To obtain this result, you can add a nickname to the name of the person:
Profile → Facts → Name → 
Across Family Gem the nickname will be automatically displayed in quotation marks between the name and the surname.
Marge Simpson is the actual name, but Marjorie Jacqueline Bouvier was her name at birth.
Abraham “Abe” Simpson is better known as Grampa Simpson...
How to manage two or more different names for one person?
In these cases a standard solution is to add multiple names to the same person.
To add a new name to a person:
Profile → Facts →
When a person has more than one name in Profile → Facts, you can reorder them by long press on the name → Move up / Move down.
The first name of the list will be displayed across Family Gem.
You can also add a type to a name:
Profile → Facts → Name →
Predefined name types are aka, birth, immigrant, maiden and married.
But you can enter a type of your choice, for example self attributed.
