Cut cardstock to fit pre-folded card (usually 4 X 5-1/2). Cut white cardstock 1/2" smaller (3-1/2 X 5). Take one beverage sized paper napkin (something with a pretty design)and cut it in half. Peel the white layers (sometimes 2 layers) away from the pattern layer. Using Mod Podge Gloss Lustre and a bristle 1" brush, apply Mod Podge onto white cardstock piece. Working quickly, lay the peeled napkin pattern side up onto the Mod Podge and smooth with fingers. Then using a 1-1/4" seam roller roll over entire area to smooth out. Apply small amount of Mod Podge on the back of the white cardstock around the edges. Trim excess napkin to 1/4" and clip corners. Now turn down the excess napkin where you spread the Mod Podge. Roll it with the seam roller. Turn face up, and apply Mod Podge Sparkle, using the same brush, lightly over entire surface, being careful not to apply much pressure or the napkin will tear. Once this is done, set aside to dry while you put the rest of your card together. Now you are ready to adhere the napkin part of the card. On the backside of the napkin card, apply double-sided scotch tape (permanent). Center it onto the main card and apply using the seam roller to ensure a good stick.
Alternatives: If you want to stamp a greeting onto the napkin, you may do so using permanent ink. Be sure to stamp before you apply the Sparkle Mod Podge.
NOTE: Only white or off-white cardstock will work for the napkin portion of the card. Colors bleed through and ruin the effect.