HP's are quirky little machines. They always have some trick or release lever to get the keyboard off. Usually its located in the battery section, after the battery has been removed. Essentially page 54 is telling you to take out the screw holding down the keyboard. (which should have a little keyboard icon etched into the plastic) After you remove that, look for another hole (could be the same one but doubtful) in the battery section, stick a precision tool in it and push a little until you see the keyboard come out. It will POP and its one piece, so don't be alarmed.
Taking apart laptops is never fun. Because generally speaking opening them up enough to expose the logic board is rough. Lots of screws and no real access points. Essentially you make sure you have ALL of the visible screws disconnected, and start opening.
In this case, the keyboard will probably not come out very far. It will most likely just lift up a little, allowing you to grab it and pull it the rest of the way.
1) If the keyboard still does not want to come out, make sure you have all screws gone. Then check again. Then check again. Ignore the manual and use your eyes. Also make sure you have opened every access panel to ensure there is no "hidden" screws.
2) Once you do get the keyboard to come up, DO NOT PULL IT AWAY. It is still connected to the logic board via a thin flex cable. Unlatch the locking clamp securing it to the logic board. Generally the easiest way to do this is to lay it down keys facing down.