You can edit a Client by selecting it from the top list in the blue section and editing the data in the fields in the green section.
Another way to create a Client (on Mac OS X only) is to drag and drop a contact from Address Book or a vCard file into the Client list. This will create the client with the information available in the vCard, and also create the default Contact for the client with the vCard information.
Clients can also be imported from delimited text using File Menu > Import > Delimited Clients.
When a Client is created, Studiometry will automatically fill in the date and Client ID. For information regarding ID formatting, Click Here.