All you need to do is find a free hosting service, create an account on the website and you'll be given a subdomain where you can access your website, for example
http://yourname.domain.com. When you register you will also receive an e-mail informing you how to access the storage where you can upload your files. Make sure that when you export your website, your first page is named
index.html because hosting providers are configured to recognize this type of file to load the first page of the website in case it's exported as HTML.
If you managed to create an account and get the details from the website then you need to upload your website by using an ftp client like FileZilla. Download the software and install it and start it from your desktop. You can use the wizard to perform a connection to the FTP using hostname, username and password you received in your email based on a successful registration. After this process you will have a window with 2 panels: left one (Local) and right one (Remote). From left to right, drag all the files and folders and wait for the upload to finish then you can check your newly uploaded website at the address they specified, for example