How do I add Values to a List Field?
Navigate to the Base Tool (on the Table that you wish to edit), then locate the specific Field you wish to update.

Expand the Field Info.

Submit entries into the Values box.

Key-Value support is also available.
Ex) Key{Value} - in this case "Value" will be stored in the dataset when chosen, but to the end user "Key" will be displayed.
Click the Save icon to save the Table.

Congratulations, you added Values to the List Field!