Amorim will take charge at Old Trafford for the first against Europa League opponents Bodo/Glimt.
He said today: "It will be a special time. I just want to win the game. Before the match it will be like a new sensation. After the whistle, it will just be another game. We have a lot of games and we are in the beginning of something. We will try to win every game, not just focus on this game and have a clear of idea of how to play.
"I am expecting a tough game. They run a lot and we need to improve that. They have some special players in the wings. They are winning all the time so I am expecting a very, very intense game and a good game. It will be a good game.
"It is a different league and it is harder than in Portugal. But I also have experienced players who play in their national teams. Having a lot of games without time to train means it will be difficult for me, but be tougher for them."
On his system, Amorim also said: "It is not a surprise. These are different things. I have to use the names of the players to explain the situation to you guys. I have explained why we had some problems in the first half. It was not a problem with the players; it was about me. I believe we can play in different systems. Sometimes we defended in a 4-4-2 (vs Ipswich). We have to play in different systems because nowadays teams change their dynamic. I think our structure, the power of this structure, is to change formation in each game."
On their goalscoring problems, he also said: "I think there is a concern in that, but we have to improve as a team. We controlled the ball in the second half (vs Ipswich) but we were not dangerous. Rasmus (Hojlund) and Josh (Zirkzee) will score more goals. Amad has to be better nearer the goal. Bruno has to score more goals."
On Marcus Rashford, Amorim added, "That positon is not the best for him. He was fighting with two giants. We will keep looking for solutions. He will have all the help of all the staff and fans. He is a Manchester United boy."