Table Position

I read the beginner's guide and understood most of what I was reading (but applying it will be a diffrent story). The topic of what I did not understand nor could I find listed in the glossary is: Table Position.

Do I want to sit "upstream" of a person with a big stack of chips, or "down stream" of a person with a big stack?

Do I want to sit between two big stacks if everyone else at the tables is small stacks (like I tend to be)?

Thanks for your time.

As a rule of thumb you want the player that give you more trouble to act before you do most of the time.
It is less a matter of what their stack size is and more a matter of how aggressive or passive they are, you want passive players acting after you and agressive players acting before you