Give them a box and some objects to practice putting in and taking out of the box.
Once you've created a safe space for your baby to explore, there are a lot of ways you can encourage their curiosity over the world around them. When they're too young to move around by themselves, babies respond well to a low-hung mirror and other small toys. As they develop, choose toys and objects that help them make use of all five of their senses. Give them a box and some objects to practice putting in and taking out of the box. Help develop their sensory skills by playing with sand, water and other textured items.