Answer: he did 8 important things to the story line
Explanation:
Meeting the ethereal teenaged girl Clarisse becomes the first precipitating event that causes him to start questioning how happy he really is.
A second event, close on its heels, is his coming home to find out that Mildred has attempted suuicide. These two events, so close together, upend his settled beliefs about his life.
A third event that inspires him to change is watching a woman whose books they are burning incinerate herself rather than live without books.
A fourth important turning point that symbolizes an irrevocable step into a new life is Montag's taking of a book for his own, which leads to him taking more books.
A fifth event is his encounter with Faber and their decision to sabotage and subvert society.
A sixth act is reaching out to Mildred, trying to interest her in reading. This leads to her betraying him.
Seventh, Montag kills Beatty, finishing off the repressive "father" figure and freeing himself from the bonds to his old life.
Eighth, Montag's city is destroyed in a nuclear blast, and he becomes part of the group of men committed to preserving knowledge.