Add a button to your form. Double click the button, which will bring you to the code for the button click event. Add line of code along the lines of: DF1Comm1.Write("B3:0/1", True)
Of course, you'll need to replace "B3:0/1" with the bit you want to set true. Also, the driver name might not be the same as what I referenced.
If none of that makes sense or you you want to talk more specifics, tell me more about your application. Like what exactly you are trying to accomplish (I'm trying to set B3:0/1 to true on a button press, then set it false on the next press). That sort of thing. The more details the better.