Cisco IP Routing Overview - Part 1

This is total madness! This can't never been done in real lab environment!!!!

most helpfull for biginner

Step 1: The router verifies that the frame has no error, & the frame's destination MAC belongs to the router.
Step 2: The router de-encapsulate the packet from the data link frame.
Step 3: NOW the router matches the destination address to it's routing table.
Step 4: The router Re-encapsulate the packet in to a data link frame.
Step 5: The router transmit the frame out of the outgoing interface. (per routing table)

I took the CCENT Exam yesterday, & this is on the exam! The question is tricky the way it's worded.

how router decide where or how to route? i mean i saw picture of one pc and there was 4 routers and at the other side there is another pc 
lets say first pc is PC : A connected to Router A, after that there is 3 routers and at the other side there is PC:B that is connected to router B
now if you imeagin a circle you will see pc:A and PC:B and 2 other Routers that are connected 
in a Circle router 2-3 connected with A and B
the Question is How or Why there router will choose to route left instead right
what makes him decide it? 
i mean if we get a circle of PC A at the upper Side Router A with him
then we got cable going from A router to Router 2 from left side and cable that goes from router 3 from
the right side and they both connect to router B/Pc:B
what will make him to choose one way instead other?
i hope i had explained myself well and sorry for my poor grammer 

gracia

How can i get the ppt you used in your video? I would like if it's available for download