Create two layouts. Put half the columns in one layout and half in the other (or whatever fits on a single page).
Then print from both layouts.
FileMaker cannot print to the right of its "Printable area" as defined by current page size and orientation in Printer set up.
If you want to use sliding object with resize part in the layout, using 2 layouts would fail. Then use large paper (A2 for A4 etc.) or define new paper as 2 pages width and print to PDF. PDF viewers have ability to print 1 page to multiple papers.