Lay red fabric onto your ironing board. Iron the webbing to the fabric with the paper backing uppermost. Leave to cool, then peel off the paper backing. Cut 25 printed linen squares measuring 15cm each. Position in a grid format on the webbing, right sides facing up. Press and adhere the pieces together; place a cloth over the fabrics and use a hot iron with the steam setting on.
Draw around the envelope shape onto the printed side of the fabric. Repeat for the other squares and cut out. Thread-up the sewing machine and work a line of red stitching all the way around the edge, starting and finishing on a base corner. Fold and press the corners in towards each other; then the two side flaps of the envelope, plus the base flap up over the edge of the sides.
Stick the edges of the base flap onto the edges of the side flaps. To make this process easier, use a cocktail stick to apply the glue. Use markers to colour the peel-off numbers and stick to the buttons. Attach to the envelopes as shown. Place a chocolate or sweet inside, then hang the envelopes from a length of twine with pegs.