Place the oilcloth tablecloth onto the picnic table, centering it precisely over all four sides and corners.
Fold one long edge of the tablecloth to the underside of the picnic table. While holding the tablecloth firmly, position a clamp onto the table over the tablecloth, centering the clamp between the two corners. Push the clamp onto the table firmly. Hold the tablecloth folded to the underside of the table at the corners and place one clamp into position at each corner. Repeat the same process on the opposite edge of the picnic table with three more clamps.
Fold the corners along the short edges of the picnic table, arranging the fabric of the oilcloth tablecloth neatly as you tuck the fabric up to the underside of the table. Place clamps at each corner on the short edges of the picnic table.