The center is not a physical place... it is the Heart from which everything comes (at least in this sense we are discussing).
You must look at the annual stars as they arrive in each palace... their relationship to the 7... their relationship to the natal chart's stars... their relationship to the lou shu (what star resides in each compass sector)... and how other stars and external forms and internal qi flow affect all of that. Only then do you begin to grasp what the results might be. Even so, you have to interpret it based on additional factors for each house.
I regret that the web sites and books make it sound as easy as a porridge recipe. It isn't
Don't despair. The situation may not be nearly as bad as you think.