Complex sentence: One simply makes a shallow or deep hole in the ground using the heel of his/her bthen takes turns (in no particular order) shooting their marbles at the hole, trying to see who can get closer.
Split into simpler sentences: One simply makes a shallow or deep hole in the ground using the heel of his/her foot. Everyone then takes turns (in no particular order) shooting their marbles at the hole, trying to see who can get closer.