Very new to the software, but I can't seem to figure out how to step through the script once I'm posting variables via the submit button on a page.

Here's what I'm doing. I run a php script, it has no input, so it just prints out the php/html page. I'm stepping through this and it's working fine. Once the html prints out, the user makes some selections and hits submit. I can't seem to figure out how to step from that point and step through line by line to see what is happening once submit is pressed and it sends some variables to the script for consideration.

What am I doing wrong here? This has to be an easy one, after all this is how nearly every php script runs..

Thanks for the help.