When your resin has begun to gel after step 4, you can add your first scale miniature tadpoles. If you add them too soon they will all sink to the bottom. The resin must be beginning to gel before you put in tadpoles if you want them to be found throughout the jar.
Use tweezers to place two or three tadpoles around the outside edges of the jar. Leave the first resin layer to set. Different types of greenery will cause different amounts of bubbles to form. Artificial greenery may not cause as many bubbles in the epoxy, but you will have to test it by dripping a bit of epoxy on it first to make sure the epoxy does not dissolve your plastic greenery. Any greenery should be in an appropriate dollhouse scale to match your jar and tadpoles.

