First, open up the Facebook page for which you want to create an RSS feed. Let's take for example the official page of myphone.gr.
Every Facebook page has a unique URL, in our example it's https://www.facebook.com/myphone.gr.
In this step, you have to open http://findmyfacebookid.com/ and paste there the URL you copied in the previous step. Click "Lookup numeric ID..."
You'll get a long numeric ID. Copy that.
Now you have to paste that numeric ID to the above URL and where the red X is.
And this is the final RSS feed of the Facebook page of our choice!