Hello Dheeru
First, you have to know the IP of the router, then put it in your browser and the router login screen will come out. You should know login information with sufficient privileges to configure the router.
Now, you have to define a new "rule" in the router telling it to allow application access for Bitcomet. You have to navigate and find the page responsible for any of the following: "firewall", "NAT", or "Port Forwarding" configuration. In this page, define a rule with the following parameters:
1- Application name: Bitcomet (or some other name)
2- Type of port: Both TCP and UDP. (I'm not sure if you only need TCP)
3- Port number of application: ##### (the number indicating the listening port of Bitcomet on your machine).
Then, usually, the page will inform you if you have to restart the router to apply the settings.
After that, go back to BitComet and look at the right most end of the status bar (the status bar is found at the bottom). It should display a yellow circle along with: "Blocked: ###.###.###.###" indicating that your Bitcomet listening port is blocked. Wait a moment and it should go to green indicating a successful connection.
Good luck.