How do you implement custom css on a Facebook activity feed plugin? This related post does not fully answer the question. Is this the right way?
Where does the
<fb:tag name='link'></fb:tag>
go? Inside of of the
<fb:activity site="..." app_id="..." ></fb:activity>
outside of it, before or after? I'm sort of confused...
Facebook PHP SDK: https://github.com/facebook/php-sdk
Comes with some simple examples, I would suggest uploading it to your server and tinkering with it, Facebook has a steep learning curve but here at Stack Overflow there is even a Facebook section: facebook.stackoverflow.com so just take each step at a time and if you can't get it by reading the facebook docs: developers.facebook.com then you can always ask here and I'm sure someone will be able to help you.
Getting Started: http://developers.facebook.com/docs/reference/php/
Once you have made an app, you add it to your fan page and then you will be abel to test what information you can get using the Graph API Explorer: https://developers.facebook.com/tools/explorer