Flash and PHP sending variables to database

I've made a game that works fine. I want to add a "send score" button that send the variable (score) to a php file which then will insert the variable into the database. And if it works to go to a frame that says "Score Sent!" and if it doesn't then "ERROR: Score not sent!". I've never done this before, could anyone please guide me through this step by step? Thank you so much.