Click on Client Portal -> Ticket Defaults ->  Create Default.  This will let you specify the properties of the tickets that will be created - for example, the Board or Queue of the ticket, it's Priority, Source and more. 

Some of the choices for some of the items may not appear as shown as they are configurable items in your PSA.

Client Portal -> Configurations -> Create Configuration. This will allow you to create as many Client Portals as you would with unique companies and users.

This configuration page allows the creation and customization of a client portal. Hit Submit when complete. You may edit the resulting configuration to make changes.