Verse 1 speaks of "belonging to the church". The Greek word translated "Church" is "ecclesia" which means a gathering or assembly of people. It is a helpful reminder that the Christian church is not identified by an institution or a building type or a street address. The church exists when the assembly of believers gather together in the name of Jesus. Between times the building is just a street address -- an assembly hall. Humans have a tendency to treat things as "holy" through use and to treat places where they have encountered God as "holy ground." But the holiest things we encounter are one another gathered in the name of Jesus.
Verse 2 we read of the martyrdom of the first of the Apostles (James brother of John son of Zebedee). Notice that James son of Zebedee has to be identified as "Brother of John". This is because the Lord's half Brother, also named James, is now a prominent leader in the Jerusalem Church (see verse 19 where Peter tells them to "tell this to James and to the "brothers" (also translated "believers")". The James there is "the Lord's half brother" that is a younger son of Joseph and Mary. James, John, and Jesus were all very common names in 1st century Palestine and the bearers of those names usually had other descriptors: James, brother of John, James the Elder, etc.
Peter is imprisoned and miraculously delivered from Prison. The King Herod mentioned here is not the King Herod that tried to kill Jesus as a baby (see Matthew 2). This is that Herod's, aka Herod the Great, son. Herod the Great's kingdom was divided into four sections for his four sons upon his death. Not much to say about this story except the amusing piece about Rhoda not opening the door but running in to tell people Peter was there while leaving him standing in the street.