That s definitely a topic that needs illustrative sentences, because there s no straightforward translation of "with" in Korean. 'with" + instrument can be translated either by -로 or replaced by a verb, like "using ..." (-을 쓰고). 'with' + people can most often be rendered by -하고/-(이)랑/과 or 와 (+같이 'together'), or, when you wanna make it clear that u're accompanying someone: -를 모시고 (for seniors) and -을 데리고 (for juniors). When 'with' simply states the existence of something, like 'a house with a bathroom', u shud attach a relative clause with the verb 있다 'exist': (X)-가 있는 (Y). There are still other possibilities!!!