What is the difference in meaning between below two sentence construction?
Sentence construction 1
a) After finishing my graduation I went to US.
b) After he left, she lifted one of the suitcases and placed it on the bed.
Sentence construction 2.
a) After I had finished my graduation I went to US.
b) After had he left, she lifted one of the suitcases and placed it on the bed.
I am more confused about below sentence.
The confession, police said, came after he had led them on a day-long wild goose chase.