How to run a php file?

Hi everyone!! i am new to internet programming which is focus on php.
i have a php file and i need to open it in a macromedia dreamweaver... but unluckly i cant open it..
i downloaded a macromedia application still wont open it!!

Do i need to have an IIS on my windows and a database application and a php application to run my php script??
please tell me where to download the following applications so i can start with my work... please do consider that i am a beginner in this subject..

any help will be appreciated...
thank you!!