First, remove the battery and then remove two rubber bungs which are then visible in the battery compartment. Their surfaces are flush with the battery compartment roof.

Using two notches to gain access, slide the inter-key sheet upwards, revealing 6 small screws.

Remove these screws.

Now carefully lift the top of the keyboard and angle it towards you, revealing its two ribbon cables.

Gently lift the locking tabs on the ribbon cables and withdraw the ribbons. You can now remove the keyboard.