If you are referring to the book: Harry reads an article about Dumbledore written by Elphias Doge; Dumbledores old friend. It explains a lot about Dumbledores childhood. After that harry reads another article about Dumbledore written by Rita Skeeter. This article explains more detail about Dumbledores childhood too.
The chapter is 'The Will Of Albus Dumbledore'.
Harry Potter :The Deathly Hallows part 2
Chapter 12.
The final chapter is called "A Flaw In The Plan"
Page 160
The Dark Lord Ascending
Page 529
The Ghoul in Pajamas.
In Harry Potter And The Deathly Hallows Harry gos back to Hogwarts in the 29th chapter.
-chapter 31- the battle of hogwarts
The Dark Lord Ascending
Charity Burbage.