Get yourself a good php book for beginners.
I've found the fllowig titles very useful in helping me take my first steps with php.
Essential PHP for Web Professionals
PHP by Example
PHP for the World Wide Web (a Visual Quickstart guide)
PHP in Easy Steps
You can use any of those titles as a front-page to back-page progressive tutorial or you can cherry-pick just the tasks you wish to implement immediately.
Each book/task is written in a way that you can cherry-pick without getting completely dazzled by the code you're looking at.
If you haven't already done so, install PHP on your machine.
The ability to test and run PHP scripts locally (rather than having to upload them to your online web space) will save you heaps of time and aggro.