How to set caster?

I'm just reading up a bit about DIY alignments and I'm wondering how to adjust the caster. From research I found it is best to get as much positive caster as possible usually somewhere around +2 - +4 degrees. But how do you set this..?

I found an image that Autoxcuda posted but i'm not sure I get what he means with "cam adjuster all in and cam adjuster all out"?

can someone enlighten me LOL

The car is pointed to the right. The right picture is the front cam adjuster and A-arm leg.