As YoungCoder stated, become familiar with http://www.php.net
You can search for functions, tutorials, and a vast
array of information provided through php.net.
My suggestion is to start with PHP 5.x and Mysql 4.x combo. No reason to start with (PHP) 4.3.x or (Mysql)
3.x.x at this point.
What are you looking to do with regard to PHP? Are you looking for database connectivity? Or are you just looking for some basic scripting options for a server?
Let me know what direction you are heading and I will be happy to break down code line by line for you to get you started. I know how it can be just starting out, I was at that place myself once.