How did dinosaurs get on Earth?

Could you please elaborate on the mystery surrounding the arrival of dinosaurs on our planet? What scientific theories or evidence do we have to understand how these colossal creatures first appeared on Earth? Have researchers uncovered any fossil records or geological clues that shed light on the origins of these fascinating prehistoric animals? Additionally, are there any ongoing studies or theories that aim to unravel the intricate puzzle of how dinosaurs came to inhabit our world?