FLORHAM PARK, N.J. — Instead of shelling out big bucks for a personal trainer to help him prepare for his first training camp, New York Jets rookie Quinnen Williams took an inexpensive and millennial approach.

He found tips on the Internet during his contract impasse.

“I worked out on my own. I can YouTube everything,” Williams said Friday after signing a four-year, $32.5 million contract that’s fully guaranteed. “I really don’t have to pay a superstar [coach], like super performers do. I can YouTube it.

“You go on the field by yourself — you can’t take the performance coach with you — so I did YouTube a lot. I also did a lot of stuff we do here [with the Jets], over and over. I did a lot of conditioning. I ran track a lot because I’ve seen DeSean Jackson run track all the time, so I got me some track cleats and started running track.”

Williams, mind you, is not a wide receiver like Jackson, but the 6-foot-3, 295-pound defensive lineman is freakishly gifted. After missing one practice and a few days of camp — the rookies reported last Friday — he arrived late Thursday night and “crushed” his conditioning test on Friday morning, according to coach Adam Gase.

Williams, drafted third overall, was held out of Friday’s practice as a precaution, but he will be on the field Saturday for the first padded practice.

Gase doesn’t expect Williams to have any problems catching up.

“He’s a quick study,” said Gase, who expects him to play multiple positions on the defensive line. “His football intelligence is off the charts.”

Williams could have afforded a personal trainer, knowing the size of his rookie contract, which included a $21.7 million signing bonus — $16.3 million at signing and the rest deferred to 2020.

Upon arriving, Williams was subjected to the typical rookie ribbing.

“I heard ‘Big Money’ a lot,” Williams said. “But a lot of guys know I’m not a real big spender. I’m a kid almost. I’m a real goofy, laid back, cool person, so there’s not a lot of things they said about [the contract].”

Williams, a breakout star last season for Alabama, stayed in Atlanta before training camp and worked out at Georgia Tech. He said he dropped 10 pounds from his college playing weight, lowering his body fat from 20 percent to 15 percent.

“I feel way better than I was in college,” Williams said. “I feel like I’m way stronger, way faster and more flexible. … I feel tremendous. I feel amazing right now.”

With help from the team nutritionist, Williams tweaked his diet, replacing regular protein with vegan-based plant protein. And, of course, he worked out a lot.

By himself.