I successfully installed a dimmer switch in a dinning area however, I have added additional lighting over the bar area next to it. I installed a new dimmer for the new lights by tapping into the top set of wires in the wall wires and now both dimmers are working on both lighted areas. Would you please tell me how to separate them so that they can work independently of each other? Thank you.

You really should only have to connect the two hot wires and connect the white to the other whites in the box, do not forget to turnoff power first,

Their should be a constant hot that will connect to both dimmers, then each dimmer will have a wire to connect to each set of lights. Test with a switch first, then install dimmers, this may save the destruction of a dimmer while figuring out.