How do I write PHP code to read an XML file?

I'm using Adobe Dreamweaver and I'm not sure what settings to put it on so that the software reads my code live (it says Forbidden whenever I do a .php document) But when I use a .html or .xml document the code I have doesn't work so I'm honestly not sure where to start. If the .php document being unreadable is a Server issue how do I fix that? But my main question is how do I write in php to get xml code to read?

This is the code I'm working with:


T-Shirt
12.5


Pants
45


Hat
10.5