i think this tutorial is a great start https://www.scirra.com/tutorials/1031/p ... wn-hosting
The steps you need to make:
pick a (free) webhosting package
look for the manual or FAQ (usually it is already mentioned in the mail you get after registration) from this webhost to know the ftp setting
get filezilla and write in the ftp connection details
upload your exported html directory
and hopefully play your game
if it doesn't work this could help https://www.scirra.com/manual/168/mime-types
So if you go to a paid webhoster it's important to know if the mime types are set up correctly before you pay (mail to support)