Bus from CX City to DB

[Pitot Probe]

I have the pleasure to visit Discovery Bay this weekend.
I have a sim at CX City in the morning and want to catch the DB Bus from CX City to DB.

Is this possible, or do I have to get to the airport first.
Looking at the bus schedule for DB02R it looks like it only stops at CX City on the way TO the airport but not on the way back from the airport.

So, if that's the case: Do I just get on it at CX City on it's way to the airport and then just stay on the bus as it transits the airport?

And roughly what time will it go past CX city if it leaves DB every 30min (on the hour and 30 past every hour)?

Thanks in advance!