Set up the table in the shade to keep the sun from drying out the concrete.
Pour a mound of sand onto the table about the size and shape of the leaf you are going to use. Cover the mound with thin plastic and anchor it with stones to keep it from blowing off the table.
Use the wire cutters to cut the chicken wire to about the same shape and size as the leaf.
Lay the leaf face-down on top of the plastic-covered mound.
Cover the leaf with a thin layer of concrete.
Put the chicken wire over it and cover this with another thin layer of concrete; use a trowel to carefully smooth out the edges, discarding any excess concrete.
Cover the concrete with plastic and allow the piece to cure, which should take between five and seven days. When it has fully hardened, peel the leaf off of the concrete to finish your lawn ornament.