The binder will contain his sandwiches, soda and bus tickets for his ride home. It's possible there may be an I-Pod or similar in there. Plus some crib notes for his speech.
How it works will depend on the session, they may be debating a specific motion or it could be Prime Ministers Question Time, where all the people in the various opposition parties get to ridicule him.
Labour and Conservatives are the two main parties who have had the power between them for many decades. The third largest party currently go by the name "Liberal Democrats" - they rebrand every few years, so it could change. They say whatever they want as an electoral promise as there is little chance of them making it into power any time soon.
After that there are nine other parties with elected officials, a couple of Independents and the rest are various Northern Ireland, Welsh and Scottish Parties.
And yes, these meetings happen every day - but the attendance varies greatly.