So looking at it, in order to be PIC Part 135 you need an ATP.

To fly as a co-pilot VFR you need "...at least 500 hours time as a pilot, including at least 100 hours of cross-country flight time, at least 25 hours of which were at night..."

To fly as a co-pilot IFR you need "...at least 1,200 hours of flight time as a pilot, including 500 hours of cross country flight time, 100 hours of night flight time, and 75 hours of actual or simulated instrument time at least 50 hours of which were in actual flight..."

Got it! I understand it now. Thanks, James.