Спасибо большое
Wow thank you very much for the fast answer! It helped me really much!

I have another few questions:
For example, I want to say my friend is from Russia, then I use genitive case right?
Like:
У меня есть друг, ево из России.

And another thing I don't understand is:
You wrote: "У меня нет братьев" -> Why not: "У меня нет брата" ?