Beige G3 to LCD

Hi

I have a beige G3 running OSX 10.2 and I also have and advent 14" LCD
and a unimac 82D with no instructions.

I have managed to get a display on a standard VGA monitor with the
unimac, but only at 640x480.

The LCD does not display at all with this setting. (The LCD works fine
with an old PC and a current Acorn computer).

The G3 (300 MHz) only has motherboard video.

Could anyone provide the settings (or a link to them) for the 82D,
please?

Also should the combination work?

Thanks

--
Jess