Setting the Pad width, height and position?

Hello all,

 	TPad (const char *name, const char *title, Double_t xlow, Double_t ylow, Double_t xup, Double_t yup, Color_t color=-1, Short_t bordersize=-1, Short_t bordermode=-2)

I am trying to set a Pad with and but facing some difficulty in interpreting xlow, ylow…parameters.
Can someone please help in this regard as to how to understand the width, height, and position of TPads in terms of these four parameters? Or point to relevant documentation about the same ?
Is it like width = xhigh - xlow, I think this is not true?

Thanks in advance !

Thank You