Everyone has to start somewhere. First you will need to get a server that can host the pages that you are uploading. There are many services you can use to host your site.
After getting your server set up you will need to upload your files to the server and then you can get the url for the page by getting the host url and appending the file structure to where the file is located. For example, if the page is on the root of the server, you would access it by going to:
mypage.html
If the page is in a subdirectory called pages, you would go to:
mypage.html
If you are looking to work in PHP, make sure your host server supports that server language. You can set up a local testing server you can use this helpful guide:
web_dev_begin.pdf