What aspect of post-world war 2 did roosevelt and churchill outline in the atlantic charter?

The signing of the Atlantic Charter was one of the first steps toward the establishment of the United Nations.  The charter urged that  changed in the control of any territory ought not be made against the wishes of the people concerned, and that all people should be able to choose their own form of government. It include other "UN" sorts of principles as well, such as a commitment to international cooperation aimed at improving life and working conditions for people all around the world, and for countries to abandon the use of force as a way of resolving disputes with one another.
Winston Churchill (Prime Minister of the United Kingdom) and Franklin Roosevelt (President of the United States) met aboard naval ships off the coast of Newfoundland in August, 1941.  In the document that they issued, which became known as the Atlantic Charter, these leaders said that they thought it "right to make known certain common principles in the national policies of their respective countries on which they base their hopes for a better future for the world." 
In 1942, twenty-six Allied nations signed what was then termed a “Declaration by United Nations.”  The nations collectively promised their support for the Atlantic Charter’s principles.