(1) Choose a level site. You may want to place your sandbox over landscape fabric to prevent weeds and keep kids from digging in the mud.
(2) Instagarden® rails have a small hole in one side. Start connecting the rails together one at a time. Make sure that the holes all face the inside of the sandbox and the pointed end of all the connectors is toward the ground.
(3) Arrange your sandbox in its location to create a regular polygon. Hold landscape fabric down with staples around the edges of the sandbox and also in the middle.
(4) Fill with sand and enjoy.