settle down in something—
1. make oneself comfortable in a seat:
- He made himself a quick meal, poured a drink and settled down in an armchair.
2. establish oneself in a new job, place of residence, etc.:
- It didn’t seem likely that we should meet again, as Clarence had settled down in the country.
settle down to something—give one’s whole attention to smth.:
- She then took out a novel from her handbag and settled down to reading it.