May I ask what your native language is? This is easier to explain if you speak spanish, portuguese or french. The difference is the same as French savoir and connaitre.
Znám is a knowledge you achieved without a learning process. You know your neighbours, you know how to get somewhere because you go there all the time. Víš is a more of a learned knowledge. You know how to calculate a root of 9 or what is the tallest mountain in the world. There is a gray area where these words overlap but this is the baseline.