I think this website explains how to use "sapere" and "conoscere" very well. Maybe it will help you :) https://www.thoughtco.com/italian-verbs-sapere-conoscere-2011690
Colloquial English English would accept "that" or "which". Yes, deep down, there are rules which favour one over the other, but English especially is dynamic and plastic, and in this case we are learning Italian anyway. Generally the English favour communicating over cleaving to rules.