Sam Darnold hopped on the bus at 6:45 a.m. Friday and headed from his hotel to the Jets’ training facility, eager to start his NFL career.Darnold knows he won’t get it all done at once this weekend, at the Jets’ rookie minicamp. He knows this is a process for him, going from third overall draft pick to potential franchise quarterback savior for this success-starved franchise.But as Darnold approaches rookie minicamp — and its three practices from Friday through Sunday — there are a couple things in particular he wants to accomplish.For one, he needs to get more comfortable with calling pre-snap audibles at the line of scrimmage. It was something he rarely did at USC. Darnold said “getting used to that” is a goal for him this weekend, as he gets back on the practice field for the first time since late December.He also must familiarize himself quickly with the Jets’ playbook, and what new offensive coordinator (and quarterbacks coach) Jeremy Bates will require of him. After these three rookie minicamp practices, Darnold will have just 13 spring practices — organized team activities and mandatory minicamp — before training camp begins in late July.And that’s when Darnold’s competition with Josh McCown for the starting job will begin in earnest.Darnold got a copy of the Jets’ playbook when he arrived at their facility the day after they drafted him — one week ago Friday. He spent the past week, leading up to rookie minicamp, trying to absorb as much of it as possible.Thursday night at the hotel where Darnold stayed with the Jets’ other rookies, he spent some time going over the playbook with the offensive players. And on Friday morning, Darnold wasted no time meeting with Bates, to ask him questions he had about the playbook.