How do I get PHP and MySQL?

A backtick is the lower-case character on the tilda key in the upper left of standard keyboards. The backtick looks something like a backwards apostrophe.

As for your main question, you can get PHP & MySQL from PHP.net and MySQL.com; however if that’s your level of expertise you might want to try something like MAMP: Mac – Apache – MySQL – PHP.

Unless you are trying to set up a local installation of WordPress on your own computer, you will be running WordPress on your host’s server. That host will almost certainly have PHP and MySQL already installed, and will provide you with tools to set up to a MySQL database.