you guys are richards
think of a port as a bridge that you and your friend want to meet on
there are like tens of thousands of bridges, and unless you specify one specific bridge, you and your friend will never see each other. your friend, in this case, could represent a game server or a website.
though you can say what bridge you want to go to, you can't cross it until your friend has opened the bridge's gate for you. opening the bridge gate is the same as opening a port.
questions?