If you want to give yourself orthodox perspective on the place of councils in the Church and their authority you might also want to read
this article by Fr. Georges Florovsky.
Actually, you will notice that this hyperlinks you to one section of the article. If you scroll up to the
top you will notice that there are actually four sections. The entire article would be useful to read, but this is a very long article and the link I first gave in this post is probalby the most relevant part (although the
first section of the Article is important as well)
John