en_tn_condensed/act/13/05.md

city of Salamis

The city of Salamis was on Cyprus Island.

proclaimed the word of God

"proclaimed the message of God"

synagogues of the Jews

Possible meanings are that 1) there were multiple Jewish synagogues in the city of Salamis where Barnabas and Saul preached or 2) Barnabas and Saul started at the synagogue at Salamis and continued to preach in all the synagogues they found while they traveled around the Island of Cyprus.

They also had John for an assistant

"John Mark went with them and was helping them"