Sewing machine hitting plate when trying to pick up thread?

I bought a Homemaker sewing machine in excellent condition which had only been used a couple of times. I removed the double needle to insert single.. looked at manual for the stitch setting for plain stitching and that was it. Have not been able to get it going. No matter how many times I do things I can't pin point what I need to to to get this going. What is it that I need to do..