What Scotts90ranger said above is correct.
You need to loosen the nut (yellow), then you'll have to break loose the ball joint stud taper by beating on the axle beam right next to the bushing with a hammer (or maybe thread the nut upside down onto the threads to protect it, and then beating downward on the stud itself might pop it loose... It can potentially be a PITA). Once the taper is broke free, you lift up the bushing (orange) past the nubs, and rotate it to adjust the camber (caster), then push it back down, engaging it with the nubs.
Because of the older D28 design, there are only 8 positions you can put the bushing (if you get the above-mentioned 2-piece eccentric bushings, the amount of available adjustments becomes much greater).
Are both of your front wheels cambered in at the top about the same amount? If so, an easier way to fix this might be to simply add a few 1-1/4" I.D. washers under your lower coil spring seats. This would gain you a half-inch or maybe a bit over increase in suspension height at the same time as correcting the negative camber.