To get a web site up and running you need to choose a Domain Name, ie the name that you type in after the www.
You will need to decide on the extension after the Domain Name ie .co.uk or .com, there are more to choose from with some costing more than others to use.
A Web Site needs a Web Server. A Web Server is a computer that is permanently connected to the Internet and permanently online. These can be a single computer or a set of computers. Independent businesses who offer space on their set of computers are called Web Host's. If you already have a webhost you can use them or a years use of my web host is included in my basic package.
Then you will want some pages of text and images that will form your web site. These pages of text and Images are called Site Content.
A Domain Name is made up of alphanumeric characters and a hyphen if you wish, my-domainname for example.
The exact name you can have will depend on what names have already been registered. If your name is John Smith you are unlikely to be able to get johnsmith.com as it will have been registered a long time ago. Not all registered domains have web sites, many are dormant.
You will also need to be 'found' by search engines such as Google or Yahoo will your site be optimised for these? Your new site will be optimised for Search Engines as part of the package but Google and other search engine rankings will depend on the amount of traffic your site generates as well as the relevance of the content.
You will also need a host with sufficient bandwidth to accommodate your site.
Bandwidth is a general term that is used to describe the amount of data that is sent and received through a specified path.
Website Bandwidth is the measure of how much data is downloaded from your site to every computer that lands on your website. (Every time someone lands on your website they download some data from your site to their computer.)
Broadband Bandwidth is the amount of data that your broadband provider allows you to download (and upload) through your link with them in a given period.