Ah! Golden Sunshine!
My Logan didn't know how to play either, go figure. Anyway, I sat in front of her and rolled a tennis ball. When she sniffed it or touched it I praised her. I also had to show her "squeekie" toys cause she was petrified and wouldn't go near them. It took about a week, but now, shoot, you can't get one away from her!
Thank you so much for fostering him! I'll bet he'll become an excellent ball catching/couch potato in no time! {HUGS to you!}