Adding a new customer to Autocase can be done 1 of 2 ways, you can either:
Open a new project, next to the customer name input box, click on the folder icon. This is opens the list of the current customers on your database, click the button at the bottom of this window labelled "new customer". Fill out all the fields and click save.
On the opening screen, click the customer tab above the toolbar and then select "Add new customer". Fill out all the fields and click save.