Well, let me see if I can make some of this make sense for you...
Lets start by relating a web server to a building and a business. If you want to general public to come to your business, you must do the following:
a) Build or rent a building
b) Advertise to let them know what you business does, and where to go to get to your business
c) Open the door so they can walk into your business.
d) Have sales people that have been trained on the products and/or services that you offer.
e) Be prepared to sell the products and/or services you offer, which includes accepting their payments.
Now, if any of those 5 are not in place, you cannot successfully conduct business. There are other things like needing an accountant, a bank account, and all that other stuff, but I'm trying to keep this simple.
Now you might be asking what does that have to do with a Web site? A lot. Lets take the 5 points above, and see what happens.
a) Buy a server, or pay to use part of a server in the cloud. Then install your web server on it.
b) Advertise so people know you have your web site, and what they can find there.
c) Open port 80 so people can access your web site. Port 80 is the default port to use.
d) Offer forums or help staff to answer peoples questions.
e) Have a digital shopping cart setup to accept orders and to process their payments.
If you take step c away from either example, it complicates people being able to get to you, since they cannot simply walk in the door. Could you use a different port? Yes, but again, it complicates things needlessly.
If you decide to do this, I highly recommend leasing space either in the cloud, or from a professional company that is responsible for the security of the server. Otherwise you will most likely end up with serious problems on your server, and from the sound of things, you would not know what to do to correct that. Running a web site these days is a challenging affair, even for the best in the business.