Put on the appropriate shoes. Put the palm of your hands at a shorter edge of the slide board. Do a push up. Slide your extended legs back, and then forward. Repeat for four sets of ten repetitions.
This is a good exercise. You'll feel it!
My third book, Pocket Guide to Fitness, is available on http://www.authorhouse.com and http://www.amazon.com. If you look up my name on those Web sites, you will find my other books The Boy in a Wheelchair and Life, Work and Play: Poems and Short Stories.