Join a shul wear most or all men wear black hats, wear a black hat yourself, wear white shirts and a black kippa only (velvet or non-knitted cloth), base your halachic practice and hashkafic views on those of yeshivish gedolim, adopt the minhagim of people at your new community, etc. But there’s a lot of variation and there’s not one set of practices you need to adopt.
“Charedi” is a general term for Orthodox Jews who are not MO. That includes Yeshivish, Chassidim, and some Sephardim like those associated with the Shas party in Israel. Outsiders refer to all non-chassidic charedim as Yeshivish but in “Yeshivish” circles people mean something slightly different and more specific by Yeshivish. So I know people who I and most people would call Yeshivish but they don’t call themselves that. As someone mentioned charedim is a term used mostly by outsiders.