From the Main Menu, select Franchise. Choose a team. Simulate everything.
(Off-Season, Pre-Season, Regular Season, Playoffs, Super Bowl, & Pro Bowl.)
The Off & Regular Seasons take the longest to simulate.
Once the Pro Bowl has finished, the year will go up by one.
Simulating 30 years will take you 4 hours, BUT you can come back to it at a later time.
Your progress does save.
You WILL occasionally have to hit the A or Start button to advance.
This is mainly caused by coach firings, which are arguably natural in the NFL.
The Achievement popped once I reached 2033, deemed as The End of Franchise Mode.
Hope this helped!