Ad manager confuses me like no other google product.

What I'd like to achieve:

• set it up do do things differently depending on geo location of the visitor
  (mainly I want to treat US visitors different)
  
• set it up to give me back full html control of much like the alternate ads of
  adsense do when they find no ad inventory (I use alternate ads to display
  affiliate stuff, but I need html, it's not pointless banner.
  
• set it up to have a minimum earning of sort so that I can minimize the
  crappy adsense ads
  
• set it up to have a number of impressions in different areas of the site
  (right now the ad balancing I run myself uses odds for affiliate promoting
  stuff and target impressions for sold inventory) But those odds and target
  levels differ on different areas of the site.
  

Ad manager manages so far one thing: confuse me.
Anybody got it figured out and can explain it in normal terminology in a step-by-step fashion ?