Manchester United players have already had a taste of Louis van Gaal's methods after the new manager, who is officially unveiled in the role today, ordered double training sessions just two days into the pre-season.

Van Gaal, smiling and looking relaxed after arriving from his stint as Netherlands manager at the World Cup, was given a tour of the Carrington training facility by his new assistants, recently-retired United star Ryan Giggs, and Albert Stuivenberg.

The Dutchman introduced himself to the players individually but it is understood that he is waiting for the return of those enjoying post-World Cup breaks, including striker Wayne Rooney, before he addresses the squad as a whole.

Van Gaal, 62, a noted disciplinarian, has been asked to make United a force again after last season's disappointing campaign under David Moyes in which they finished seventh and failed to secure European football.

In Brazil, where he guided the Dutch to third place, he said he was aiming to instil the same team unity at Old Trafford.

"I hope the group in Manchester will become like this one," he said after the Dutch ended their World Cup campaign with a 3-0 victory over Brazil.

"We have to sing from the same hymn sheet."

The squad containing new signings Ander Herrera and Luke Shaw, who were brought at a combined cost of £56 million ($95.88 million), depart for the United States for a pre-season tour on Friday.

Van Gaal, who has won titles with Ajax, Barcelona, Bayern Munich and AZ Alkmaar, will take charge of a United match for the first time on July 23 against the Los Angeles Galaxy.