Flip the coffee maker on its back

Using a right angled rachet screwdriver, with a Philips No.2 head, unscrew the stainless steel filter from the underside of the top section.

It will probably be filthy and need cleaning with hot water and a scrubbing brush. Use a pin to remove any blockages from the holes of the filter. You can also use a TeePee dental brush to remove debris from around the screw hole where the water comes out.