Draw a path from every cat to his very own milk bowl. The numbers next to and below the diagram indicate how many cells are used in those particular rows and columns (including the cats and milk bowls). Cats walk only horizontally and vertically and no cell is visited more than once.
The website allows you to draw cat paws on a path in either direction, but your answer will still count as correct if some (or even all) of them are heading in the wrong direction, as long as the path itself is correct.
To start, we will try to find out which cells are used by the path. We can see that only one cell in the leftmost column is used by the path, and we mark it as such. Then the other three cells in that column are empty. Now, the first, third and bottom rows have only three possible cells that can be used. Finally, the remaining cells in the second row have to be in de second and fourth columns, as can be seen from the clues below the puzzle.
Now, we still need to find a valid path through the marked cells. Starting from the bowl of milk, we can only go to the right. Now, if we would continue downwards, the cell above it could not be included in a path anymore. Therefore, we continue upwards. Now the path must follow around the empty square until it comes out right of the cat. To finish the path, there is clearly only one way left in which the cat can reach that cell while going through the remaining marked cells.