how is this done on a 96 lumina apv?

FIrst make sure the auto adjustment or rear shoes is done, otherwise extra e brake pedal travel will be longer . Rear brake shoes adjust WHEN BRAKING HARD GOING BACKWARDS. NO need going fast, but brake hard....a dozen or 20 times in a row. If only mild braking is usually done in reverse, they do not adjust . Of course, the auto adjustment must be in operating condition....otherwise, make the adjustement manually (tighten till you start feeling resistance to rotation then untighten a bit)
Then, and only after that, you will know if you still need adjusting the e-brake cable. There are NO details about that in the book..but I'd check (and I will..I'm not sure) over the middle of rear axle where the front cable meets the rear cables to each wheel...I've always kept the rear brakes tightly adjusted..and I never had to look at the cable adjustment...if any.