How to Configure Router to Forward Specific Ports?

[#1]

I have the Thomson TG585 V8 router.
I need  A.  To check which ports are open, B.  To be able to open specific ports.
From the documentation there seem to be two levels of firewall but no explanation of how to configure specific ports
Any help appreciated

[#2]

It's been a while since I used a 585 but I think on the menu there's an option for 'Game and Application sharing' that should allow you to forward ports through there.