Trumantwo

After I have played a board, how can I use the double dummy feature to evaluate the score? I see the notations of '=' and a dot with a '1' or '2'. Can I use these to arrive at the optimal contract for the board.

I would like to know how I use the double dummy feature to evaluate my play on a board. I see notations of "=" and perhaps a dot containing '1' or '2'indicated on cards within a suit. How does this relate to my what is possible on a particular contract.