2. They are all on the second floor, and the boarding gate of each flight is different. Depending on the airport adjustment, it may not be fixed.

The boarding pass will indicate the boarding gate of your flight, which will not change under normal circumstances, and you will be informed under special circumstances.

4. Changing boarding pass is handled at the check-in counter where the airline is located. If the airline you bought the ticket doesn't set up a check-in counter at the airport, you can do it at the check-in counter of the airport agent.