Please DO NOT firmly remove any connectors. Most connectors have locks. In step 20 you can see the two different colors of the connector the bottom is black and the top (the lock) is brown. Each side of the lock sticks out further than the connector. One side at a time pull back on the lock. Connection should come out with no force. to reconnect, seat connection and push lock back in place. If any issues try unlocking and re-seat connection.

Remove battery FIRST before you do anything. Then remove all the screws on the back of the computer. The you can go to the front and follow all the steps afterward.