were shocked

That is, "were very surprised" or, "were amazed."

ordinary

That is, "common" or, "lower-class." Peter and John were simple fishermen.

That is, "who did not have a formal education." This could also be translated as, "who had not gone to religious school."

This could also be translated as, "But then they thought about the fact that."

This could also be translated as, "had spend time with Jesus" or, "had been taught by Jesus."

The leaders said that they would punish Peter and John if they continued to teach people about Jesus.

That is, "allowed them to leave."

These references may be slightly different in some Bible translations.