anpa - ground; low, deep; to lower, to defeat      
insa - inside, stomach
monsi - rear, back, behind
sewi - high, above, roof, top, sky
sama - same, similar
tan - reason, cause; because of
poka - side; beside, nearby, with

The use of anpa, insa, monsi, and sewi

Since these words aren't prepositions, they are free for other uses, just like any other noun/adjective/verb.
You have to use another preposition along with these words.

   ona li lon sewi mi. -- He is in my above. He is above me.
   pipi li lon anpa mi. -- The bug is underneath me.
   moku li lon insa mi. -- Food is inside me.
   len li lon monsi mi. -- Clothes are behind me.

   monsi ,as a body part, can mean either the back or the butt
  
   anpa as a verb mi anpa e jan utala -- I defeated the warrior

 
The use of sama, and tan

sama
   jan ni li sama mi. -- That person is like me.
   ona li lukin sama pipi. -- He looks like a bug.
   sama li ike. -- Equality is bad.

tan
   mi moku tan ni: mi wile moku.
This literally says I eat because-of this: I want to-eat - I eat because I'm hungry.

poka

poka as a noun/adjective
   ona li lon poka mi. -- He is at my side. He is beside me.
   jan poka -- neighbor; someone who is beside you
   poka telo -- water side; in other words, the beach

poka as a preposition
   mi moku poka jan pona mi. -- I ate beside my friend.
   mi moku lon poka pi jan pona mi. -- I ate at side of my friend.

 Here is another example:
mi utala e jan ike poka jan nasa. -- I fought an enemy with a drunk guy.
mi utala e jan ike lon poka pi jan nasa. -- I fought an enemy at the side of a drunk guy.