Join Joe Wicks on his YouTube channel.
https://www.youtube.com/channel/UCAxW1XT0iEJo0TYlRfn6rYQ
Or you could do a Cosmic Kids Yoga workout.
https://www.youtube.com/user/CosmicKidsYoga
Or you could even come up with your own workout! Write it down/draw it and ask your family to join in!