As with all quoted manufacturers' instructions, I will ask for permission in due course, but thank you in advance.
The nose mask can be disassembled for cleaning (see section "Disassembly"). If the tube is stretched tightly - which should never be the case, but happens every day - the nose mask can fall apart when it is put on. It is therefore really important to me that you know the individual parts and can literally master the assembly in your sleep. As I said, I gave you masks to practise on, so please do that.