The correct answers to this open question are the following.
Who were the four main powers negotiating at the Congress of Vienna?
The four powers were Austria, Prussia, Russia, and Great Britain.
How did they benefit from the territorial arrangements?
They benefited from the territorial arrangements in that they reorder Europe after the Napoleonic Wars in which Napoleon had conquered big portions of land to be included in the French kingdom.
After the war, with the new territorial arrangements, these four European superpowers of the time divided the territories according to their political and economic interests Concert of Europe.
How did the powers enforce their commitment to preserving the traditional socio-political hierarchies?
Through the negotiation of important treaties that each delegate proposed in order to maintain respect and order in the region, avoiding wars as a form of resolving foreign issues.