to become familiar with somewhere new, such as a new house, job, or school, and to feel comfortable and happy there: Once we've settled in, we'll have you over for dinner.

settle in (third-person singular simple present settles in, present participle settling in, simple past and past participle settled in) (idiomatic) To get comfortable or established, as in a new place.

settle in (to) (something or some place) To become comfortable in and accustomed to a new location, environment, or circumstance.