Browser tries to download install.php

Trying to install WP to my server. Downloaded the WP installation and amended the config file correctly. I uploaded all these files into a directory named ‘blog’, but when I attempt to go to /blog/wp-admin/install.php to finish the install, my browser tries to download the PHP file.

I have not installed PHP on the server as I think it was pre-installed. Is this an issue with my PHP installation?

Any help for this noob would be appreciated!