What should the Gentiles do? The church in Jerusalem concluded they should write a letter to the Gentiles in the other churches that affirms the truth of the Gospel they heard from Paul. Circumcision and law keeping are not required for salvation. Paul and Barnabas gladly take the letter back to Antioch.
What is happening? The spread of Gospel to the Gentiles was not in itself surprising, but the pouring out of the promised Spirit on uncircumcised Gentiles caught many Jews by surprise. Some even objected. Finally, James addressed the meeting that what was happening was in line with prior Scripture revelation.
What about him? Peter once asked Jesus about what would happen to John. That wasn’t for Peter to worry about. In this chapter, Peter gets rescued from prison, again. That is not Jame’s story, though. He is martyred by Herod Agrippa 1. Of course, Jesus told his disciples it would be this way.