Select a contact from the contacts list and then press the Edit contact button in the contact properties area on the right to start editing it.
In the upper part of the contact edit area are the name and organization fields as well as the contact picture to be uploaded.
The lower part shows the same groups of contact properties as the Contact Details structured with tabs and boxes.
Some properties have a type selector drop-down where you can select what type of email address (e.g. home or work) this is. Remove a contact property by either clearing the input field(s) or by clicking the Delete icon right next to it.
When done with editing, save your changes by clicking the Save button below the form. Abort editing and discard your changes with the Cancel button.