Complex sentence: In the 2008--09 season, FC Twente hired former England manager Steve McClaren as new boss: under his tenure, unseeded Twente entered the draw for the third qualifying round of the Champions League, being drawn against seeded Arsenal.
Split into simpler sentences: In the 2008--09 season, Twente hired former England manager Steve McClaren as its new head coach. Under his tenure, unseeded Twente entered the draw for the third qualifying round of the Champions League, being drawn against seeded Arsenal.