I forgot to ask you the following question. I included a few other questions. Thank you very much.

1) When giving instructions on what to do before boarding a plane to a person who has never flown, shall I use "you have to", "you + simple present", "you should" or the imperative?
Example: You should look/you have to look/ look at the departues board to check your flight number and the departure time of your flight.
2)We were in half-board: we had breakfast and dinner at the hotel, but we stayed out for lunch. We sometimes were given a packed lunch from the hotel.
3)I stayed in a double room with mini-bar, air conditioning, a shining bathroom and a view of the city. I knew (better: met) a group of American tourists.
4) I made (?) a sightseeing city tour.
5) We visited Mozart's house (not Mozart's home)
The hotel was previously a castle, which was used to protect the people against the attack from the other communes.

1) When giving instructions on what to do before boarding a plane to a person who has never flown, shall I use "you have to", "you + simple present", "you should" or the imperative? "you should" or the imperative is correct.

Example: You should look at the departures board to check your flight number and the departure time of your flight.

2) We were in half-board: We had breakfast and dinner at the hotel, but we stayed out for lunch. We sometimes were given a packed lunch from the hotel.
I have never heard the term "half-board" - however, I've heard of "continental plan" and "American plan."<b/>
http://www.travel-industry-dictionary.com/continental-plan.html
and
http://honeymoons.about.com/od/hotelresortreservations/qt/american_plan.htm

3) I stayed in a double room with mini-bar, air conditioning, a shining bathroom, and a view of the city. I met a group of American tourists.

4) I took a sightseeing tour of the city.

5) We visited Mozart's house. (Mozart's home works fine, too.)
The hotel was previously a castle, which was used to protect the people against attack from the other communes.

1) When giving instructions on what to do before boarding a plane to a person who has never flown, it is generally recommended to use a combination of "you should" or "you have to", as well as the imperative form. For example: "You should look at the departures board to check your flight number and departure time" or "You have to check the departures board for your flight number and departure time." Alternatively, you can use the imperative form and say "Look at the departures board to check your flight number and departure time."

2) It seems like you're providing information about your dining arrangements during your stay at a hotel. If you were on a half-board plan, it typically means that breakfast and dinner are included in your package, but lunch is not. Occasionally, some hotels may provide packed lunches as a courtesy. So, in your case, you would have breakfast and dinner at the hotel, but you would have to find your own lunch options, unless the hotel offered a packed lunch.

3) In this sentence, it seems like you're describing the features of the room you stayed in and mentioning that you met a group of American tourists. The sentence could be rephrased as: "I stayed in a double room with amenities such as a mini-bar, air conditioning, a sparkling bathroom, and a city view. During my stay, I had the opportunity to meet a group of American tourists."

4) It seems like you're mentioning that you went on a city tour. To complete the sentence, you can say "I went on a sightseeing city tour" or "I took a sightseeing city tour."

5) In this statement, you're referring to a visit to Mozart's house. The correct phrasing would be "We visited Mozart's house" or "We went to Mozart's house." It's important to note the difference between "house" and "home" in this context. "House" refers to the physical building where Mozart resided, while "home" refers to the concept of where he lived and felt a sense of belonging.

Additional note: It appears that you're also mentioning the history of the hotel, stating that it was previously a castle used for protection against attacks from other communes. That's a fascinating detail, but it doesn't seem to be connected to any specific question. However, it's a great addition to your narrative about your trip!