The document produced by the Calendar template starts with two Sheets, one with a calendar for the month (and year) that the template was created, the second with a 'blank' calendar which you can set to any month and year using the pop-up menu in the Month cell and the stepper control on the cell containing the year number.
Each of those Sheets has a tab, containing its name, seen at the top of the document window. Clicking the tab brings that Sheet to the front.
Adding a new Sheet is a simple matter.
If you want a new Sheet that starts with the same content as an existing Sheet:
Click on the tab for the sheet you want to Duplicate, then move the pointer onto that tab and click the small v that appears toward the right end of the tab.
In the pop-up menu that appears, click Duplicate.
Done.
If you want a new Sheet with minimal content:
Click on the Tab for the Sheet which you want the new one to follow in the list at the to of the document window.
Click the + sign at the left end of the row of Tabs.
A new Sheet, named Sheet 1, will be added to the Document. The sheet will contain one table, named Table 1. Both those names are editable, and should be named to reflect their purpose. Each Sheet in a Document MUST have a distinct name. Each Table on a sheet MUST have a name that is distinct from the names of all other Tables on that Sheet. Giving a distinct name to every tble in the Document is not compulsory, but does have the advantage of removing the need to include the Sheet name when referencing a cell on that table with a formula in a cell on a different table.
"Sheet" in Numbers has the specific meaning you may have gathered from the information above—the Sheet is a large canvas on which the Tables and other objects (text boxes, images, charts, etc.) are placed.
Sheets may be thought of as being in 'stacks,' one behind the other, but they're only 'left' or 'right' of another sheet in the sense that their tabs have that relationship in the list across the top of the window.
If you want to place a Table to the right of the Calendar table, you don't need a new Sheet. There's plenty of room on the same Sheet for the Calendar table and a notes table to sit side by side on one Sheet (even if there's not enough room to see both of them on one screen).
In fact, the document produced by the Calendar template has four tables on the sheet displayed in my post above.
The month and year are in two cells of a three column table with 14 rows, where much of the data needed for the calendar is stored or calculated.
The Month before and Month after calendars are two more tables on this sheet, and the Current Month calendar is also a separate table from the others.
More to follow when I've read the posts you've sent while I was writing this one.
Regards,
Barry