Htimings and Vtimings Parameters

[Austin Howard]

I need to know what the parameters to HTimings and VTimings mean, and
how to determine the correct values for these. Using Modes "1280x1024"
in my Screen section and Display subsection, causes an error saying that
particular mode is not found. Upon reading the manual I learned I could
manually specify that mode in the Monitor section in the Mode portion.
Which as you know requires the HTimings and VTimings arguments. The
parameters hsyncstart, hsyncend, htotal and the vertical equivalents are
unclear to me. 
Thanks for any help,
Howard