The connotation of this sentence is to find a stable home, but the expression is somewhat special. It uses some symbolic words and metaphors, such as "Swallow Crossing the Sea" and "Bird's Nest Crossing the Water", suggesting that the author is facing some difficulties and challenges, and this "friend" may refer to a person who can provide help and support.
The author is looking for a place to stay, but this place seems hard to find. The author may feel lonely and helpless and need a friend to support and help him. At the same time, this sentence also implies that the author is experiencing a wandering life and needs to find a stable home.