Trace reindeer template twice on thin cardboard, once right side up and once upside down, so that the outlines touch at the tops of the figures. Cut out, and fold where they're attached. The figures will have tabs at the bottoms. Cut out a card; fold in half.
For the reindeer, make two slits the length of the tabs, parallel to and equidistant from the card's fold. Tuck one tab into each slit, bending the cardboard where it passes through the slits. Glue the tabs to the underside of the card; to finish both, glue cards into a larger pre-folded backing.