This should help:
https://support.chess.com/customer/portal/articles/1444875-what-do-the-computer-evaluation-numbers-mean-like-2-25-
I don't have Winboard, so not sure about the evaluation graph. And I think the second number refers to how far ahead the program searched to come up with it's + or - score.
In my Winboard, I notice strange numbers beside the notation
1. e4 e6 {-0.19/19}
What does the numbers on the left and the right of the backslash mean ?
And, I also want to ask about the evaluation graph.
I see a white bar and a black bar above the axis/below the axis.
What does it mean ?
Does it mean a better position for White if the white bar is above the axis and vice versa ?