Complex sentence: The carvings were executed on the polished surface of the tusk with a silex microburin from top to bottom, one register after the other, placing first the main figures and then carving the places where the figures meet, such as the arms of the combatants.
Split into simpler sentences: The carvings were executed on the polished surface of the tusk with a silex microburin from top to bottom, one register after the other. The artisan first carved the main figures and then carved the places where the figures meet, such as the arms of the combatants.