Can't find my server IP

Hi. I'm a new server owner and I've been trying to get my server out on PMC. But the problem is I can't find my IP. I really need help. I have been using localhost not my server IP for most of the time and I don't know how to portforward it if I haven't already. You see, this was my server when I was still using my brother's computer and his account. So, he used a flash drive and downloaded all the server files into my computer. He portforward it on his computer. Do me or him have to do it again on mine or is it just that something is wrong? Every time I look for my IP online it says its this: 75.171.64.85

I tried it myself and it doesn't work. Help!