A well-designed environment encourages children to feel happy and confident to participate in experiences provided within it. This makes it easier for children to achieve the desired objectives from the experiences.
Whether the environment is indoors or outdoors, the materials and experiences you provide need to be arranged in an inviting way. Each environment should also include various places for children to undertake different types of play.
If materials are dumped on the floor or in the sandpit, this does not show a caring, thought-out plan. Instead you could arrange buckets and spades so that they are ready for use or display and set up the trains on their tracks. You should also re-set these play experiences during the day for other children.