Continuos Rotating Servo

Hello.

Can you please tell me how parameters i need to use for moving my continuos rotating servos in visual basic? I have tryed many ways, but i really don't understand what is the 'versus' parameter (up and down) and what is the speed parameter (faster and slowest).

Can someone give me an example please?

Thank you and scuse me for my bad english.

Ema from Italy.