The pump can not be cleaned directly it sits behind a filter.
Instructions for cleaning the filter can be found on page 6 of the manual here.
In essence you need to remove the cover at the bottom of the washer, there should be a a hose which you can pull and put in the bowel to drain the water and tap the cap off at which point the water which sits at the bottom of the washing machine (a litre or two) will come out. Ones that had drained unscrew the cover and pull out the round filter, and wash it under a tap, replace it, screw the cover back in place, fold away the hose and then run the washing on a rinse to check water isnt leaking from the filter.
Should you need anything clarified please let me know.