The Council Members are members of the Alliance Assembly. They represent their member states during meetings of the Alliance Assembly in Parliament. This is conducted virtually and run on Turner's World in Alioth.
They are elected by the people of their member states. The electoral rules differs between member states due to their history. The number of Council Members within the Alliance Assembly is based on the size of each member state's respective populations.
The Council Members elect the Prime Minister of the Alliance. If there are major disputes in the Assembly then the Council Members can cast a vote of no confidence against the serving Prime Minister. If the vote passes then the PM must resign and a new election is held.