I cant host my session of HU2 it keeps saying it cant be reached by players. i tried both BYOND help and Port foward if anyone knows how to get past that please tell me and il make you a gmod in my hu2 server :)
You're going to need to port forward the BYOND port you are hosting on.
Look up instructions for your router here:

You usually can find what model router you have by looking at the physical router itself, it's usually a sticker on the back.

Also check to make sure your Windows Firewall allows it.
(Or any other software-based firewalls you have.)