Hello, we went yesterday to a shelter. And we saw a blue fatty cat and we took it. Now we are trying to socialize him,he's really shy and scared. Does anyone have some tips how to make him feel at home? ..The shelter calls him ''Kasjmier'' but we call him ''Boris''. :-)

boris seems like a nice name ^.^ I adopted my puppy from a shelter and he was very fearful at first. You just have to leave him be for the first few days. Let him get familier with the house. Then over the span of about 3-4 weeks then you socialize. Maybe try to play games in every room in the house (or every room he is aloud in) so He can get a sense where he can have some play time.

It just takes a little more time with shelter pets ^^.

I changed my dogs name too, the shelter named him maqueen we call him bear :).

It really depends on the cat. Some cats can adapt right away, others take a few weeks. The best to do is keep him in one room for a while so he can calm down and get used to being in a new place. After a few days, open up the door and let him start to explore. He needs to do it at his own pace as well. 

Defiantly give him some time to adjust.
Let him show intrerest in you.
I voluteer at a cat shelter and have two of my own, and many cats are like this.
Tiger,  years after we've had him, is still shy and chosens when he wants to socialize with.

If he approaches you, you can show interest in him, like maybe sticking out your hand, or touching a toy. But it'll probably be a while before he wants to even come in contact.