Jesus preached Amillennialism in his gospel of the Kingdom. So the best place to grasp a deeper understanding is in a search of the 4 gospels for the characteristics of the Kingdom. It is one reason why the Pharisees rejected him. They expected the physical Millennial Kingdom based on a literal reading of the Kingdom Prophecies. Many do the same today.

But a physical kingdom did not show when Daniel said it would. It was instead a spiritual and hidden from all but the born-again.

So it remains hidden to all but the born-again even today.

Peter preaches the Amillennial gospel of the Kingdom at Pentecost where we can glean the details.