WC3 Ladder games and port forwarding, help

[Pleasehavemercy]

Hi, i'm new to the server. I want to play same ladder games but i always get disconnected.
Now from my research i need to "port forwarding" to start playing
i saw some tutorials but i my modem is a
ARRIS
MODEL: TG2482A
The page say
If you can't find your exact router model in the list below then select one that seems similar. Most Arris routers have a similar interface. Finding a similar guide should work just fine for you.
¿Which should pick? Also, im playin from SouthAmerica, idk if that is a problem