The complete manual is there to help you at [URL]http://www.phpnet.com[\URL].
If you know absolutely nothing about PHP, I suggest you get a quick-start book. As for visual basic ... I get the impression that a lot of web programming languages are very similar. Knowledge of one programming language and of the whole concept of computer programming will help you to learn quickly.
I had no knowledge of programming before I tackled PHP and I still feel like a total beginner, but I discovered lots of similarities of concept between PHP, Javascript, Java, C++ and so on and so forth. If you know visual basic, you'll probably move forward very quickly.
Best o luck
Norman