Ten Hag is without 12 first-team players as United take on the Bundesliga champions in Germany on Wednesday.
This includes Raphael Varane, Mason Mount and Harry Maguire, who have not travelled to Munich.
"There was always something, but you have to deal with it," said Ten Hag
"I think I never started the best starting XI. That is football. You have to deal with it. I love these situations. You have to know what to do and focus on the process."
Defender Varane and midfielder Mount both took part in the open section of training at United's Carrington training centre on Tuesday morning to raise hopes they would be able to return from injury for the opening game in Group A, which also includes Turkey's Galatasaray and FC Copenhagen from Denmark.
Varane has missed the past two games and Mount three, with United making an underwhelming start to the Premier League season, losing three of their first five games.
Centre-back Maguire also trained on Tuesday, but picked up an injury which rules him out.
Ten Hag is also missing forwards Antony and Jadon Sancho, who are not training with the squad at present, plus Dutch midfielder Donny van de Beek, who is not registered for European games.
Saturday's 3-1 defeat to Brighton at Old Trafford on Saturday leaves United 13th in the Premier League table, but Ten Hag says his side are not in need of a major reset.
"No, we don't feel we need that," the Dutch manager said. "We are in a process. In parts of the game we play well. In parts of the game we play below our levels. We need to be consistent for 90 plus minutes."
