# laid hold of Paul

"took hold of Paul" or "arrested Paul"

# commanded him to be bound

"commanded his soldiers to bind him" 

# with two chains

This means they bound Paul to two Roman soldiers, one on each side of him.

# he asked who he was and what he had done.

"he asked, 'Who is this man? What has he done?'"

# he asked who he was

The chief captain is speaking to the crowd, not to Paul.