BC means Before Christ. Hence, 65 BC is 65 years before Christ was born, whereas 29 BC is only 29 years before Christ was born.
Hence, 29 BC is more recent when compared to 65 BC.
AD means Anno Domini, and follows the normal chronological order.
So, 65 BC is the farthest past, followed by 29 BC and 6 BC. This is followed by AD years in chronological order, 1718AD and the most recent being 2020 AD.
Thus, the correct order is 65 BC -> 29 BC -> 6 BC -> 1718 AD -> 2020 AD.