Typically you select a web hosting company, buy a hosting plan from them (making sure they support whatever server-side languages you need), register your desired domain name (typically done through your hosting company, but doesn't have to be), and upload your files to the hosting server on which your account resides. There are other options, most requiring much more work on your part, but generally using a shared hosting plan for somewhere in the range of $5/month (depending on the features) or a virtual private server from a hosting company for maybe $20+/month would be the most common options for private individuals.