It can take them a while to learn how to play with toys. Many never knew how to play before they were adopted. It took several years for one of mine. My guys have always like grunting toys, such as hedgehog and duck stuffies.
My guys also like to play in the yard. I do a half hearted playbow and they run in return.
Your dog is very, very new and it may take a while to feel comfortable enough to play, especially with people around. Relax and keep a quiet environment and all will be fine.