Well, I'll leave it for somebody else to confirm, for I am not much of a linguist myself, but I think the "ordinary" passive voice (I really don't know what else to call it, but I am sure there is a term for it) is used very rarely. I mean, sentences like "Táto budova
bola postavená/Toto mesto
bolo založené v roku..." (This building was built/This city was founded in...) do exist, but they sound a bit too formal to be used in everyday conversations. Nobody would say "Táto kniha bola napísaná (-týmto autorom-)" (This book was written by (-this author-)), we would go for "Túto knihu napísal (-tento autor-)" ((-This author-) wrote this book) instead.
There is, however, this other construction that is used quite often, which is probably what you were asking about. It sounds like passive (and maybe it really is, gramatically; I must admit I don't know) and is often translated as such into English, because it focuses on
what was done and does not mention
who did it. Examples I can think of right now include:
"Sedí
sa mi tu dobre"/"Je mi tu dobre" = "I feel good here", "I like it here"
"Často
sa to robí takto" = "It is often done this way"
"Roztrhla
sa mi taška", "Rozbilo
sa to", "Stratilo
sa to", ... = "My bag has been torn", "It got broken", "It got lost", ... (literally "It broke itself", "It lost itself"). I think this is the most usual way we use this kind of "indirect passive" (ehm, most likely I am really making a fool of myself now, somebody with more linguistic background please come up with the real term for this). My parents often mock us with "Spravilo
sa to samo, že?" ("It did it itself, right?" (?)) when we break something and say it isn't our fault
So the key word in these constructions is "
sa" - the same "
sa" we use with reflexive verbs, but here it usually means "it", or that we don't know/don't care who, does something.
In cases like "Čaká
sa na XY" ("We are/Everybody is waiting for XY"), "Musí
sa chodiť okolo" ("We have to/Everybody has to go around"), it even means everybody, all of us.
Other more or less common examples of these impersonal constructions:
"Nechce
sa mi" - ("I don't feel like it" (?))
"Zdá
sa mi to" - "It seems to me"
"Ukázalo
sa, že" - "It turned out that"
"Zabudlo
sa na to" - "We/Everybody has forgotten about it"
"Práve
sa tam píše písomka" - "They are sitting a test there right now"
"Vezme
sa prvý výskyt slova v texte, a nahradí
sa týmto výrazom", "Pridá
sa mlieko a celé
sa to mieša niekoľko minúť" - when we describe a working process of some kind
Is it more clear now? Have I answered your question?