Trying to understand how potentiometric titration works

 

I made a cell by placing magnesium and copper electrodes in sodium chloride solution (salt water or brine). The potential difference due to the reactivity difference is in milliVolts. I am thinking that in potentiometric titration, there is a similar set up with two electrodes in a solution. Another solution is run in from a burette and this affects the potential recorded. The stuff I've read about potentiometric titration is complicated. There is a lot of talk about Gibbs' Free Energy - I can't do that yet. So this is my opening thinking on the subject.