Stafford learning the playbook doesn't mean how to run a play. It more means the names of the plays, how they're called, and what the coach is looking for in them.
This is still football. Throw to the open guy. Hand the ball off. Avoid the pass the rush. Read the D, and take what it gives you. Not as simple for a young guy; a whole lot easier for a guy with so many games under his belt as Stafford. He's seen every D there is. What I expect is that his passing percentage will be mediocre to start the season and go up as the year goes on as he gets more accustomed to his Receivers and the route timing. But the plays? The whole playbook will be open starting with the Bears game.