Once the screws have been removed from the board, use a plastic opening tool to gently pry up the board and expose the mode switch assembly underneath.
Lay the board down gently and out of the way.
Take care not to damage any of the wires or the board itself.
Remove the top of the mouse which will separate from the under side once the screws are removed.
The metal connection near the yellow screws on the top left of the mouse assembly falls out very easily. Make sure to replace the metal connection with the prong pointing up. Otherwise, the mouse will not work correctly.