Complex sentence: IWPR is an international network of three partner not-for-profit organisations governed by Boards of Trustees comprised of senior journalists, peace-building and human rights experts, regional specialists, and business and NGO professionals.
Split into simpler sentences: IWPR is an international network of three partner not-for-profit organisations. They are governed by Boards of Trustees of senior journalists, peace-building and human rights experts, regional specialists, and business and NGO professionals.