You can reach to the Da Nang Airport through numerous connecting flights via Bangkok and Hong Kong. Some of the flights which operate on this route include Air India, Bangkok Airways etc. From the airport you can take a cab which would leave you in this town.
Visa is required by the citizens of India to enter the country of Vietnam. You can either apply for Visa at New Delhi or can apply for the same online. You can also apply for Visa on arrival. Cost of a single entry visa is approximately Rs. 1500/- while for multiple entry it is Rs. 3000/-
As mentioned before this place doesnêt have any airports within it. The closest airport is the Da Nang airport which is known to have flight landing in it from Hanoi etc. From there you can easily take a cab which would leave you here in town.
You can take motorbikes or cabs from Da Nang and can reach this place via the Marble Mountains. You would also get a cab from Quang Binh or Hue to this place at a pretty affordable price.
Again the closest railway station is in Da Nang from where you can take a public bus or taxi to reach this place.
Most of this town can be covered on foot, however there are options for Motorbikes and taxis available. However due to government regulations you arenêt allowed to move with vehicles in certain older parts of this town.