Generally your external businesses have been added during dashboard creation but if you are using a new Business then you can add them and their staff on the fly during the log-out item process. Super handy if you were not aware of the new appointment.

This makes it faster to get keys or items out directly whilst saving the details permanently, just start to process your items out as usual, then select Business Tab, first search in the drop down to make sure the Business was not already created. If not, then click the small Tool icon next to the box and begin populating the details.