The everything sign reminds me of a full table spread during a banquet. To sign everything, form both hands into fists and face them upward as you swing them both in towards the center of your body. As they swing center and cross each other, gradually open them up to number 5 hands as they swing apart from each other again, both palms still facing up.
Teach your baby or toddler the everything sign when you are describing how everything is present in front of you for them to choose from at the store, in the park or zoo, or simply in front of your fridge and kitchen table. Showing your toddler everything can either overwhelm them or excite them, but it is a good opportunity to help them exercise their autonomy by picking and choosing based on their growing preferences.
Teach your child this sign when they have everything in front of them to choose from: food, toys, animals to feed at the zoo, and so on.