Sit upright in a chair in front of a table.
Place your hands on the edge of the table.
Have an assistant support your weaker hand on the table, or use your stronger hand by placing it on top of your weaker hand.
Lean forward with your body, bending your elbows and take your chest towards the table.
Push through your arms to straighten your elbows and return to sitting upright.
As this becomes easier, move the chair further back from the table.