Question

Who were the members of the concert of Europe?
What was the idea of "balance of power?"​

Answer 1

The balance of power theory in international relations suggests that states may secure their survival by preventing any one state from gaining enough military power to dominate all others.

In this case, I could only research this part of your question. Try reading an article about the Concert of Europe.

Hopefully, someone else is capable of fully answering your question.

I apologize for my inconvenience.