Create a node type that acts like a PHP page?
First, you will need to enable the "PHP filter" core module in admin/modules.  I think you did.

Then, you'll need to configure the newly added text format in admin/config/content/formats and assign some role to that text format.  Note that you can also do this from admin/people/permissions.

Useless to say you'll need to be very conservative here and only allow this text format to - very - trusted users (roles).

Finally, in your node content, select the "PHP code" text format and type your code (including  tags).