"We do not know the names of those streets."
Translation:Jména tamhletěch ulic neznáme.
It's the same difference like between "saber" and "conocer" in Spanish.
"Znát" means "to be to be acquainted or familiar with". It is used with accusative and usually when talking about people. For example "Znám Matěje" (I know Matěj).
"Vědět" means "to possess knowledge of" and is used with locative plus preposition "o" (Vím o tom. - I know about that.), accusative (Vím to. - I know that.) or followed by ", že" and dependent clause (Vím, že jsi vrah. - I know that you are a murderer).