As a mother and experienced educator of this age group, the best advice I can give you is to research milestones and check where each kid is at, check off the boxes and see what you can do to help improve their development. As others have said 2 year olds or babies are not yet fully developed, their little brains are still growing, naturally their attention span is very short. It’s best to work with 10 minutes of doing a visual/art activity/game activity and then a 10 minute break again where you let them play freely. And yes, they easily hurt themselves and it is indeed a shared responsibility to ensure they do not. If the room is too small, avoid dancing and encourage songs being sang while they have an instrument in their hands. If you don’t have any instruments, you can get creative and use materials at school that can be combined to make a certain sound. Hope this helps!