DrakX has a very comprehensive database of monitors and will usually correctly identify yours.
This option allows you to set two critical parameters, the vertical refresh rate and the horizontal sync rate. Vertical refresh determines how often the screen is refreshed and horizondal sync is the rate at which scanlines are displayed.
It is VERY IMPORTANT that you do not specify a monitor type with a sync range that is beyond the capabilities of your monitor: you may damage your monitor. If in doubt, choose a conservative setting and consult your monitor documentation.
This is the default option and tries to determine the monitor type from the monitor database.
If the installer has not correctly detected your monitor and you know which one you have, you can select it from the tree by selecting:
vendor
the monitor manufacturers name
the monitor description
selecting this group displays nearly 30 displays configurations such as 1024x768 @ 60Hz and includes Flat panel displays as used in laptops. This is often a good monitor selection group if you need to use the Vesa card driver when your video hardware cannot be determed automatically. Once again it may be wise to be conservative in your selections.