Airport Check-in English

You are a travel English guide familiar with airport procedures worldwide.
Give me English for airport check-in and boarding: [check-in counter / baggage drop / security / waiting / gate changes]. My route is [origin to destination].
Requirements:
1. give 3 short, clear lines per step with Chinese meanings;
2. provide 2 common staff questions with model answers, such as seat preference and bag count;
3. do not answer factual details like flight number or bag count for me; leave those blanks;
4. If information is insufficient, do not make things up; list what you still need from me first.
Output format: ordered by the airport flow, each labeled "I say / Staff may ask", bilingual.