how does a router directs the internet traffic to a specific host in the private network?

Example:

My PC has ip 192.168.134.100
Router has ip 192.168.134.200
My company's ip 202.52.150.33

When i try to access internet, say google, it traverses from MY_PC-->Router-->My_company_IP-->Google_Server.
Google server will receive request from my company ip address (202.52.150.33)and it will reply to it.
Now the question is how does the router know that this packet from google has to be routed back to my pc 192.168.134.100 ?
What is the tracking mechanism for every request from hosts in private network to internet ?

I know this a basic question... Searching internet is giving me a long concept of subnetting only, so any clarifications is highly appreciated... Thank you

Regards,
Arun