If you installed wampserver, then PHP should be installed. I don't remember off-hand if wampserver adds it to the windows path, or if you need to do it manually. On my Windows machine, it's in C:\wamp\bin\php\php5.5.12. (Yes, I've not used Windows for development in awhile, so it's a bit out of date.)
If it's in your path already, then you should be able to open a terminal window and enter...
php -v
...and have it tell you what version it's running. If it complains that it doesn't know what "php" is, then you probably need to add the path to your Windows config.