I cant change the stitch on my singer 7422, any ideas?

I am newer to sewing, i have a singer 7422, that i have been using for a couple of years now and i cant change the stitch. I push the buttons, but it will only alow the first row to light up. I have looked in the manual, but I didnt see anything regarding my problem. Please help, this is my escape from the stresses of life. Thank You.