FLORHAM PARK, N.J. — Austin Seferian-Jenkins said Thursday that he wants to leave the past in the past. But the past now lives on YouTube.

“I’m not going to speak of the past and I’m very thankful for the opportunity that I have here,” the Jets’ new tight end said Thursday, almost a week after his DUI and the infamous dash-cam video that has made the rounds on TMZ and beyond. “There’s an agreement here and an understanding of what’s expected of me. Like I said, I’m not going to speak of the past. I’m going to take full advantage of it and really approach it as hard as I can and go as hard as I can.”

Although neither Seferian-Jenkins nor coach Todd Bowles would go into specifics about the “agreement,” it’s a good bet that it involves staying out of trouble. This was the 23-year-old’s second DUI — he was charged in 2013 while at the University of Washington — and he also was kicked out of practice with the Bucs in the offseason because he was unprepared.

Bowles reiterated Thursday that Seferian-Jenkins has a “clean slate.” Bowles previously said he hasn’t watched the dash-cam footage but has heard of it.

The video shows Seferian-Jenkins stumbling away from his car early last Friday morning after being pulled over in Tampa, Florida. After speaking with police, who offer to let him go with a warning for speeding and weaving through traffic, Seferian-Jenkins keeps talking, demonstrating what appears to be a high level of intoxication. Once arrested, the conversation turns crude, though not confrontational, in the squad car. He was cut by the Bucs hours later, and the Jets picked him up Monday.

“He has a clear understanding of what I expect,” Bowles said. “Of course, anybody’s going to come in and say all the right things, but your actions speak louder than your words . . . and we’ll see what he does.”

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Although Seferian-Jenkins has practiced for the Jets for only one day, offensive coordinator Chan Gailey is impressed with his skill set. “He’s a good-looking young player,” he said. “He looks like a guy that’s going to play and have a role on our football team in some way, shape or form.”

Bowles, however, said he’s not sure if Seferian-Jenkins will be activated for Sunday’s game against the Seahawks because he has plenty of catching up to do.

Gailey said it probably will take four or five weeks before the tight end gets fully acclimated to the offense, but if his practices justify it, the Jets could use him in a limited capacity.

Seferian-Jenkins, a second-round pick in 2014, always has had a fairly high upside, but his career has been sidetracked by behavioral issues and injuries. At 6-5, 262, he has the size and speed to make an impact at a position that’s been an afterthought for the Jets after they cut Jace Amaro before the season.

Although Seferian-Jenkins repeatedly declined to speak about the incident, he did say he received words of wisdom from Brandon Marshall — words he doesn’t intend to ignore.

“He’s definitely helped me out a lot and given me all the resources I need in the city to get the help that I need, to have the support that I need,” Seferian-Jenkins said. “I’m really appreciative of that. I’m really thankful that he reached out to me. It means a lot to me.”

Before his diagnosis with borderline personality disorder and his work as a mental-health advocate, Marshall had run-ins with the law, including a DUI.

Seferian-Jenkins declined to say if he believes he has an alcohol addiction or if he is seeking treatment, but he did say he is “excited” about a few of the things Marshall suggested.

“I will be using those resources and I’m looking forward to it,” he said. “I have to hold up my end of the bargain and do what’s expected of me.’’