Can someone tell me how to turn the sound on? – ABC Genius - Preschool Games for Learning Letters Review

I like this app very much. But I can’t seem to get the sound to come back on. Also, I purchased the full App. And then deleted it bc I thought it might be a glitch. Now it says that I have to re purchase it.... I really hope someone can help me. Thanks.
Review by trudeaus8 on ABC Genius - Preschool Games for Learning Letters.