Complex sentence: The award is contested by the twelve winners of the year's Philips Manager of the Month Awards, which are open to Irish sports managers, trainers or coaches, or overseas-born managers of Irish teams.
Split into simpler sentences: The award is contested by the twelve winners of the year's Philips Manager of the Month Awards. Those eligible to win the award are Irish sports managers, trainers or coaches, or overseas-born managers of Irish teams.