The file must have a header row with these columns in any order:
season,game_number,date,away,home 20002001,1,2000-10-05,DET,COL 20002001,2,2000-10-05,BOS,TOR 20002001,3,2000-10-07,TOR,MTL
Team tricodes must match those used in your teams data. Duplicate game numbers for the same season are skipped.