OK, my cat Kingston does not know how to use the liter box... when he was a kitten, he would use it all the time, now that he has grown, he only wants to do his buisnes in my mother garden. And my mom doesn't like it. Not a little bit. So how can I make him to use it?

Your problem isn't that the cat doesn't know how to use the litter box, it's that he finds the garden to be a better place to go. Which is going to be difficult to change... the garden is cleaner and better smelling than the litter box, simply because it's not enclosed. The dirt is nice and soft, easy to dig in. And by going out there, he is helping to mark his territory.

The best thing I can suggest is making the garden less inviting, which means putting down gravel, chicken wire, or thorny branches. Some people say orange peels work. And some say that planting rue will keep the cat out of an area.

This may not get him back to using the box, but it may get him to pick a different spot out side to go at. You might also try putting a box out in the garden... hopefully he would go there, which can be scooped and cleaned out, and avoid the rest of the garden.

I agree that you will need to make the garden less appealing. You could also try making the litter box more appealing. We had some difficulty with our cat (chose the basement floor over her box) and we added a product called Cat Attract (you can find this at most pet stores or online) to her litter box. You can use the product as the litter or, as in our case, we sprinkled some on top of the pine pellet litter we already used. Within a couple of days she had stopped using the basement floor and gone back to her box.