The sentence that is punctuated correctly is:
"After driving all day and night, we finally reached our destination, and we happily went to sleep."
The other sentences contain punctuation issues:
- "in 2019 eight new students enrolled in our school..." - should have a comma after "2019."
- "for about 3 minutes, the helicopter hovered overhead, and then flew away, to the east." - the comma after "away" is unnecessary.
- "on monday i am going to go hiking but after that i will come by to visit you." - should capitalize "Monday" and "I," and it might be clearer with a comma before "but."