There are two ways, depending on how you plan to assemble your calendar.
First, you can choose the Spiral-Bound Calendar in the start-up menu. This section suggests two calendar types- one has the month grid and the photo on separate pages, the other has them on the same page. Choose the Spiral-Bound section if you want to assemble your calendar on a spiral.
If you need the pages to be stitched, then select the Booklet calendar for 12 months in the Custom Calendar section. This type uses the Smart Print module that arranges everything automatically, so a certain grid and a certain photo will be printed on the same page. All you need to do then is just assemble the booklet to create your own calendar.