The sign for park is a compound sign, combining the signs for grass and area. This sign is best used if you're going to a public garden or grassy park with your baby.
However, if you want to specify that you're taking your baby or toddler to the garden with a playground, then you make another compound sign for park, which is play and then area.
We use park contextually when we are ready to head out for play time or our afternoon walk. Consider teaching your baby or toddler both signs for park, to allow for clarity so that your baby knows what to anticipate.
Teach your baby or toddler the different signs for park to let them know whether they'll be spending time among the flowers and trees, or with friends at the playground, or a little bit of both!