From Wikipedia:
The film is set at various stages in the career of Apple co-founder Steve Jobs (Fassbender).
Flashbacks show Apple co-founder Steve Wozniak (Rogen) and Jobs creating the Apple II, revealing that Wozniak's ideas made the product successful. Jobs then discusses company politics with CEO John Sculley (Daniels); they talk about Jobs' life as an adopted child, and Jobs admits that his need for control stems from his feelings of powerlessness in being given up.
Bored with the computer industry, Jobs starts working as a surf instructor, topping up his income by playing saxophone in a nightclub. A stint as a car mechanic doesn't end well after he is sacked for consistent lateness and slapdash attitude, although he progresses to become the garage's most successful used car salesman of 1989.
In the 1990s, sickened with the false patter of the used car trade, Jobs retrains as a school bus driver.. He becomes a popular figure with teenage students at George Washington High in Outer Richmond, where he also works as a janitor, before sadly dying of cancer at the age of 56.