How do you prepare to be a first-round draft pick? Pray, work out and be ready for a surprise.

The NFL draft has a way of keeping everyone in the dark right up to the moment its blinding light is beamed upon the next young man whose life has just changed forever.

An informal survey at 7 Vines Vineyard and Winery in Dellwood confirmed this Thursday night as the NFL’s 89th draft was about to begin.

The participants in the poll were plucked from the 100 people closest to Joe Alt, a 6-foot-9, 321-pound two-time All-America left tackle from Notre Dame and Totino-Grace High School.

“I have no idea what’s happening,” said girlfriend Emilie Meyer, who met Joe in Spanish class at Totino-Grace and is now a junior at Drake University. “I try not to pay attention to mock drafts because they don’t seem reliable. Besides, all we have to do is wait until tonight to find out, right?”

Smart.

We can thank Joe’s mother, Carolyn, for assembling everyone on this peaceful, idyllic property far, far from the NFL’s glitz and glamour.

“Joe just didn’t want to go to Detroit for the draft,” Carolyn said.

Too many people. A record 270,000, to be exact.

If it had been up to Joe, he’d have spent Thursday night with a few people at the family cabin in Amery, Wis. On the dock. Fishing with no cameras to feed reactions to ESPN and NFL Network.

“But we got a lot of people, five kids and 10 of Joe’s nieces and nephews with three more due in the next month,” Carolyn said. “We needed more room. We needed a compromise, and I won.”

Joe was glad she did as he arrived. Dressed casually in white sneakers, gray pants and a dark blue pullover, he worked the room looking awfully calm for a guy who still didn’t know the Los Angeles Chargers would surprise everyone, including him, by making him the fifth overall pick about an hour or so later.

“I think I’m more nervous than Joe is,” said older brother Mark, a former NHL player drafted 53rd overall by the Carolina Hurricanes in 2010.

“I’m more nervous than the day I was drafted,” said father John, the 21st overall pick of the 1984 NFL draft by Kansas City. “The attention is so much greater now. I know the money sure is, too.”

John’s rookie deal with the Chiefs was worth $1.8 million over four years with a $750,000 signing bonus. Today’s rookies are paid according to a predetermined scale. Last year’s fifth overall pick was paid $31.9 million over four years with a $20.2 million signing bonus. Joe will get a bump for inflation, no doubt.

Joe and most of his inner circle were convinced the Titans would take him at No. 7. Joe had visited Tennessee and considered that his best fit because of the coaches and their need at left tackle. He also visited the Jets, who had the 10th pick, and the Giants, who had the sixth pick.

Joe’s agent, Tommy Condon, flew in to be with him on Thursday night. With the draft already underway and Condon having spent the day speaking to multiple teams, the agent said, “We have a range from number 3 to number 7, but we think it’s going to be the Titans.”

Condon brought caps with logos of the Patriots, Cardinals, Chargers, Giants and Titans just to be safe the moment Joe got the call.

The Chargers were showing strong interest at the combine when coach Jim Harbaugh sat down with Alex Boone. The former Vikings offensive lineman had played for Harbaugh in San Francisco and was working with Joe as a trainer at Training Haus in Eagan.

“I said, ‘Coach, you are going to love Joe,” Boone said.

“But then that interest went away,” John said. “And the Chargers’ need is at right tackle, so I put them to the back of my mind.”

In hindsight, it was Harbaugh feigning disinterest to avoid the risk of the Giants trading ahead of the Chargers with the Cardinals.

Bill Welle, the sports performance manager of Training Haus, was partly responsible for helping Joe confirm his top five status with a strong combine performance.

“Since they’ve been doing GPS testing, zero to 5 yards in the 40, no offensive linemen ever ran as fast as Joe’s 14.14 miles per hour,” Welle said.

Yes, NFL predraft scrutiny has gotten that precise, folks.

“I’ll put it this way,” Welle added. “Joe’s the best offensive lineman I’ve ever had in 32 years of doing this.”

Notre Dame head coach Marcus Freeman, who was at Thursday’s draft party, said there were times he actually had to tell Joe to slow down.

“Joe’s all about the work and going a thousand miles an hour,” Freeman said. “For the protection of others, sometimes you had to tell him, ‘Hey, Joe, it’s a walk-through.’ ”

In some ways, Thursday night felt like gameday for Joe and his inner circle. That’s why Father Nels Gjengdahl, Joe’s priest since he was a first-grader at St. Odilia in Shoreview, handed him a little saint medallion, a longtime gameday tradition at Notre Dame.

“That meant a lot,” Joe said.

So how did Joe sleep the night before the biggest day of his life?

“Fine,” he said. “I was tired, so I got eight hours.”

Then what?

“Worked out for two hours at 7,” he said. “Got in a little run, a little pump. Just putting the work in. Doing what I normally do.”

He went to church to sit and pray. He went to lunch and spent the afternoon with Emilie, who came in for the day but had to drive back to Des Moines around the time Joe would be flying to Los Angeles for his introductory news conference Friday.

Any thoughts of the Chargers trading the pick were dashed when Joe’s phone rang with about five minutes left on the clock. He smiled wide as Harbaugh asked, “Do you want to be part of a great offensive line?”

Joe hugged Emilie and his mom, and pulled his dad to his feet for the biggest hug when the pick was announced minutes later on TV. Joe, sweating, let out a deep sigh of relief and barked, “Let’s go to work!” as the room cheered.

Later that night, in Los Angeles, Harbaugh opened his news conference by explaining his decision before anyone could ask why he took Joe when most of the fan base had been clamoring for a receiver.

“I know you’re going to ask, ‘What about a weapon?’ ” Harbaugh said. “Offensive linemen we look at as weapons. We talk about attacking on offensive. Offensive line is the tip of the spear.”

In Dellwood, Joe Alt and 100 members of his inner circle agreed.