If you are getting Web space as part of your deal with an Internet Service Provider, go to their support page and see what it says about uploading your pages. It may specify a method of choice for FTPing files and even offer software for you to download to use. If you get confused, pick up the telephone and talk to a support person. This area of computing gets into computer lingo quickly, so don't be hesitant to ask for some handholding from support or geek friends that you have. Whatever it's called, it is based on links, also called hyperlinks.
Links are just what they sound like, connections from one page to another.
The visitor clicks on something and is taken to another page. Also, pages can have links to the elements that make up that page, such as images. These must be there for the page to display correctly. This means that the link to the image's file has been lost or broken. Image files must be uploaded along with web pages to the web server and be placed in a directory on that server that is similar to where it was on your computer.