New cases are added from the Cases page. You get there by clicking the logo in the top left corner of your screen.
Once you are at the site click the Add New Case button at the bottom of the page to create a new case. Follow the instructions to enter the minimum information needed to open a new case. Once you've done that you will be taken to the Deceased & Case Details page where you carry on filling out more information
The system will take you through the various pages that it thinks you need to complete when you click the Complete & Continue button. Your entries will be automatically saved if you use this button and you will be taken to each page in turn.
You do not have to complete everything on a page before continuing. You can just click the Save button and then navigate to another page. When you click the Complete & Continue button on a page the system will mark it as completed. If you want to change the page back to "incomplete" use the drop-down box at the top of the page next to the title.