The IARU Constitution sets out the overall governance of IARU. Whilst all three Regions of IARU have their own Constitutions, they are keyed in to the core elements of the global IARU Constitution.
The IARU Constitution can be found here.
Regional Constitutions govern matters of relevance to the Region, whilst the IARU Constitution governs matters of membership of IARU, its objectives and the roles of the Administrative Council, International Secretariat and the Regions.
The region 1 constitution can be found here.