I am working on Jetson board in my office and the Jetson connected to my office internet. I want to set up an external access that allowed me to work on the board from my home.
You should ask this problem to the IT of your office. They prepare the network environment to you.
The logic is applicable to all the computers/devices in your office.
FYI, the Jetsons use ordinary DHCP for assignment of IP address. The Jetson also uses a standard SSH port. A router won’t know which computer to forward to unless it is told the Jetson is the correct system to forward SSH to. If you don’t have admin access to the router, then you will probably need to arrange for an alternate SSH port to be forwarded to your Jetson, and then when calling to the Jetson from the outside world you would use that alternative port. Do you control the router? This is why the IT department probably needs to set this up.