3th person plural :

kedileri vardý

except the last one:they had a cat=kedileri vardý not(kedisi vardý !!!)

tessekürler I allways mix it

And: Annemin kedisi vardý, is it ok?

Cok tessekürler!

I an thinking more and more about this grammer:

Annemin kedileri vardý

So if my mother had more cats, is it like this?

Saðol

"annemin kedisi vardý" is OK.

"annemin kedileri vardý". Yes... my mother had more than one cat. 

kedileri vardý is ambigous and depending on context may mean

kedileri vardý =she/he had cats (more than one cat)

kedileri vardý = they had a cat ( one cat)

kedileri vardý = they had cats (more than one cat)

From the context (=what you already know) it should be clear which is which

çok teþekkür!

I have problems now with the word "merdiven´

Ok, go upstrairs is: yukarý çýkmak

go downstairs: aþaðý gitmek

But how do I say I am going upstairs/downstairs on the stairs?

Mervenle yukarý çýkarým  ? Mervene yukarý çýkarým ?

´Düþ´ is a dream at night or is it a daydream as well?

 It is both, however we use it more for daydream.. while rüya also means both but used more for dream at night.

 Go up the stairs, it is on your left.

Merdivenlerden yukarý çýk, solunda.

Can you go down the stairs?

Merdivenlerden aþaðý inebilir misin?

what is the difference between meþhur and önlü?

Tessekürler!