"The nights are different."
Translation:Noci jsou jiné.
'Noc' is feminine so you would need to use 'ty'. But it's not necessary here.
The first one is palatalized. Perhaps try reading the tips and notes sections?
Ti is only for nominative and animated male.
Ta is for neutral (nominative and accusative)
Ty is (in nominative and accusative) for everything else
I'd guess you need plural verb forms with plural nouns?