Creating my own Capacitor in CST

Hi,
Could anyone please tell me how I can make a capacitor in CST? I created a dielectric cube and put 2 PEC on each side. Is that right?How can I excite it?
I defined a structure in CST whit some lumped elements. when I put my own capacitor in the model I get an error " the lumped element number4 is inside PEC" but it's not. what should I do?

For electrostatic capacitance computation the CST EM STUDIO? is the right product to choose.
You'll find examples for such simulations in the online help in the tutorials section.