4Chan Replica

I'm making a 4chan replica script based of a moderately modified version of tinybb and I'm having a little trouble finding out how page requests work around here.

Say you wanna get to page 2 og /b/, the @ the end of the url you'd just type in "/g/2" right?

Problem is, I'm not sure how 4chans script uses that arg, say you appended "/" to the url as so "/g/2/" it doesn't work, so that tells me this is not a directory right?

How the fuck do I pick this up in my php script so I can know what page to deliver?

You can see it here http://autoitunderground(.)tk/chan/b/

Any way, I actually lied about getting the script to interpret the page requests in the manner stated before and realized that lying about it isn't gonna get me anywhere, can you help?

=(

In case I'm not giving ya'll enough info on this~

I have indulged myself into the mission of revealing to myself how moot's chan interprets these links <a href="1">1</a>.

Obviously, that's a request for page 1, I jus wanna know how I can  pick this up in my php script so I can know what page was requested, and the stupid mod rewrite wont work under uniserver, even though it says the module is loaded and ready to go in both server-info and phpinfo()