Complex sentence: Lt. Stone appears since the first issue in the comic continuity as the field commander of the new G.I. Joe team, is never stated at what point the team was formed but the date of 2009 is given in their first mission.
Split into simpler sentences: Lt. Stone appears since the first issue in the comic continuity as the field commander of the new G.I. Joe team. It is never stated at what point the team was formed but the date of 2009 is given in their first mission.