From your main calendar view tap the menu bars at the bottom right and choose visible calendar.   Tap the menu bars at the top right of that view and choose new calendar.

Name your calendar and add an icon or color to it if you choose.

If you have an Informant sync account setup and syncing to Informant then that calendar will automatically be assigned to and sync to Informant sync.   

If you don't have an Informant sync account setup and syncing to Informant then that calendar will become an 'unsynced' calendar and remain only in Informant on that device.

If you want to create a new calendar that syncs to google calendar, please create the new calendar from within your google calendar account online or in the google calendar app on that same device.  Then it will sync into Informant through your google calendar.