I took a quick search and found nothing. I've deduced you buy the appropriate level aug for the slot. At that point do you just put them in? Do you need a certain skill to do it? Can they be taken out/switched? Thanks!
Also, note that most augments are crafted via jewelcrafting, blacksmithing or tailoring. The augment type slot on an item is determined by its nature (i.e. metal armor, leather armor, jewelry...).
2 is smithing and goes into plate/chain armor
3 is jewelcraft and goes into jewelry
4 is not implemented yet (probably fletched) and goes into bows
5 is tailored and goes into leather/cloth armor
6 is quested and goes into instruments