How to make a minecraft server with a Technicolor TG587n v3 modem?

So i'm trying to make a minecraft server and i know how to get to the port forwarding part in the browser, i just don't know what to do from there and i've tried heaps of forums and videos and none of them seem to work

Make sure you have the ports open by using a port checker(Just google it) and if it's closed try hosting it off of a different port. Make sure you are running the server software while using the server. In the folder you put your server in there's a file called 'server' Make sure you take your IPV4 and put it in the IP address(Google how to get that) Go to IPchicken.com and it will tell you your IP. You connect with the IPV4 others connect with the IPchicken one.

The open NAT type is to configure a DMZ mode in the modem for a specific device / IP, this generally works. However if you're attempting to host games over the internet for Minecraft etc you may need to invest in a modem / router to control the port forwarding.

Just as a little hint though, both Minecraft and Terraria work fine without port forwarding via freeware called 'Hamachi' by Logmein software.