Click on the User section on the left menu
Search for the User
Click on the Bin icon to the right 
It will then ask you to input the email address from the User you are deleting
Click Delete
It will then clarify if the deletion was successful
Click on the User section on the left menu
Search for the User
Click on the Bin icon to the right
It will then ask you to input the email address from the User you are deleting
Click Delete
It will then clarify if the deletion was successful