Get a plasic box with a lid that can be taken off if needed,
a plastic pipe that fits the down pipe your “dirty” water is coming from
a plastic pipe that will lead from the box into the Wheely bin
plastic pipe corners 2-4
Some aquarium sand ( it needs to be about 2 inches, 6cm high in the box you have chosen, not stones) Some aquarium wool and Aquarium sponge (this looks like an over sized plastic scrubber)
brackets to hang the box filter from the wall
First cut a hole in the side of the filter (towards the top edge of the box) to match the downpipe size, on the opposite side cut a hole as far down to the bottom as you can) to match the filtered water pipe that leads down to the wheely, then cut a hole in the side of the wheely to match the filtered water pipe ( put this as high as you can, so that you make use of the max amount of water that can fit into the wheely).
Measure the height on the wall where the downpipes are to fit the filter. It must be higher than the wheely. Fit bracket to the wall. Now measure the distance between the down pipe of the house and the Filter. Add 4 inches, 12 cm. That will be the length of your first pipe. Attach this pipe to the down water pipe and the filter.
Now measure the distance between the filter and the wheely add 2 inches, that will be the filtered water pipe attached to the wheely.
In the filter you put at the bottom the aquarium wool (it normaly comes in sheets) cut to size to fit bottom and sides
On top of that put the aquarium sand, then the Aquarium sponge cut that to size so it fits in the box. Put the lid on the Filter it is ready to use!
Be sure to clean it out every three to six months, by rinsing the sponge ( you can lift it out to do that) and the sand with the wool by passing fresh water through. Don’t clean too often the established bacteria in the filter helps clean the water from bio residue.