In order to replace words or phrases with your own, log in as an administrator and from your administration dashboard navigate to Languages.
Over there you will be able to view a tabular list of all available languages in a tabular list.
Find the language which you want to replace the term or phrase and click on the edit icon (1) in the operations column. This will open a pop-up window where you can place on the left hand the term or phrase that you want to replace (2) and on the right hand the substitute term or phrase (3).
Note: Keep each term or phrase in a new line in order for the override of terms/phrases to properly work.
Once you have overridden a term, your new term will appear instead of the old one throughout the system (4). Please note that you will have to type the exact word and/or phrase that you want to replace. For example, if you want to replace the 'User types' as well, apart from the 'Users' wording, you will also have to add an override for the phrase 'User types'.