Supply a print-ready PDF as flat single pages in month order, cover first, with 3mm bleed and crop marks.
Page count must match the format you chose: 13 pages for the single sided calendar, 14 for the version with a printed back page, and 14 for the 7 page double sided calendar.
Do not supply as spreads.
CMYK colour, 300dpi images, all fonts embedded or outlined.
Keep critical content 10mm inside the trim, and clear of the top 15mm where the wire binding sits.