Isuzu 1993 Trooper V6 3.2

Hi!
1993 Isuzu Trooper 4x4 V6 3.2L

Truck won't start.
battery checked. It has full charge and they told me they didn't think it was an alternator issue because of the full charge.

Symptoms:
Accessory lights are fully illuminated when key is in 'on' position. When I turn the key to try to crank. There is no attempt at turnover, the accessories dim and the sounds fade. The voltage goes all the way down.
With key in 'on' position, the same thing happens if I turn the lights on (dim accessories and the sounds fade out).

I DO have a severe power steering fluid leak and there is power steering fluid all over the alternator and I am sure the connections.

The battery terminal wires have been cleaned, trimmed and new connectors put on.

I don't believe it's a starter issue as I'm not getting the 'click click' sounds.I lose ALL power when even trying to start the engine.

Single mom. Isuzus are expensive to work on, so I am trying to do this repair myself. I do NOT have a manual in order to find where all the connections are that I need to be checking /cleaning.

Please help me out here if you can. Any suggestions are MUCH appreciated.
thank you!
'Heather