Where do i catch the bus if i am staying in clifford estates? what is the earliest bus?

You mean from airport to the Clifford Estates?
If so, you can take the bus line 7B to its terminal at Hejun Square. Then walk to the Clifford Estates.
The earliest bus of this line is at around 07:15 and the last bus is at around 01:00.
If you mean the opposite side, the bus line starts from Hejun Square at around 05:45 and ends at 21:15.