Nobody can log in to my new minecraft server, but i can?

I recently made my first minecraft server, it works for me, but not my friends, how do i make my minecraft server work?
PS. I don't think it's because of the port number because i double checked that.
(this is the video i watched to make my server)-

Guest

Shch

Mallory

That has got to be the WORST video ever! You do not need to install Utorrent.

1) Set a static LAN IP on the minecraft server computer.
2) login to your router and port forward the port 25565 tcp/udp to the static IP.
3) open the windows firewall (on the server) and create an inbound firewall rule to allow the same port (and both protocols) through.
4)Go to http://www.whatsmyip.org/ to find your WAN IP.

You will be able to connect using your LAN IP from any computer on your LAN.
Your friends will be able to connect using your WAN IP.

If you are connecting from the server, you can use the loopback address or hostname; viz 127.0.0.1 or localhost (which resolves to the loopback address).

Amith