Thank you for posting the site.

The tickets can be bought either in the airport or just outside the airport near where the bus is loaded.

For return to the airport, the hotel concierge should be able to arrange for a return by the same too. (Note that some concierges may try to dissuade you, but this company's service has seemed perfectly reliable to all persons whom I have personally known to have taken it.)

In either going from the airport or returning to the airport: if one person, the bus can make a great value. If two persons, a cab may be a good value. If three or more people, the taxi is the best value. Of course that is presuming luggage will fit in one cab, which given the size of cabs and their trunks may be presuming too much -- at least with some travellers.