Complex sentence: Moffat, a fan of "Doctor Who" since childhood, first professionally contributed to "Doctor Who" with a prose story, "Continuity Errors", which was published in the 1996 Virgin Books anthology'.
Split into simpler sentences: Moffat, a fan of "Doctor Who" since childhood. His first solitary "Doctor Who" work was a short story, "Continuity Errors", published in the 1996 Virgin Books anthology'.