Possible meanings are 1) this restates "As Paul and Barnabas left" in verse 42 or 2) Paul and Barnabas left the meeting before it ended and this occurs later.
# proselytes
These were non-Jewish people who converted to Judaism.
It is implied that they believed Paul's message that Jesus was the Messiah. AT: "to continue to trust that God kindly forgives people's sins because of what Jesus did" (See: [[rc://en/ta/man/translate/figs-explicit]])