The 22-year-old, brought in to replace Lewis Hamilton after his move to Mercedes, spoke to staff at the team's headquarters yesterday.
Although Perez had previously visited the team's technology centre for a seat fitting and some simulator work after ending his two-year spell with Sauber at the end of November, the day was his first real taster of life as a McLaren driver.
"It's certainly not hit me yet, to realise I am driving for the best team in the world, that you are part of the best team," he admitted.
"It might take me some time."
The former Sauber driver intends to remain at his base in Switzerland rather than relocate to the UK, where McLaren are based, but insists that will not prove a problem as he prepares for life with his new team.
"Of course my main responsibility, my main goal is to win races, to be 100 per cent fit for every single race," he said.
"So it's extremely important to reduce the travelling as much as possible, to be focused on the team, to give my very best to the team. That is the target.
"Other than that, you need a very good balance in your personal life to be able to give everything, so whenever I do have some to myself, I will choose whether to go back (to Mexico) or I stay at home.
"My priority right now is to give my maximum for the rest of the year."
Although Perez was signed up as Lewis Hamilton's replacement on the back of three podium finishes with Sauber, once he put pen to paper he ended the year with a run of six races without a point.
With just over two months' work ahead of him before he lines up on the grid for the season-opening race in Melbourne on March 17, Perez insists such a barren spell now counts for nothing as he targets the world title.
"The past is the past, and obviously I've learnt quite a lot from that. I take the positives, and now I've a new challenge ahead of me," said Perez.
"We have to deliver, to win. The target is not simply to score points or podiums, but to win, to win the championship because when you come to McLaren you have the opportunity to do that."