Complex sentence: Carson took his first (& only to date) managerial position in October 2000, taking charge of his former club, Dumbarton, & lead the team to promotion to the Scottish Second Division in the 2001/02 season but left soon after.
Split into simpler sentences: Carson took his first (and only to date) managerial position in October 2000, taking charge of Dumbarton. He led the team to promotion to the Scottish Second Division in the 2001/02 season, but left soon after.