Nangan is an island in the Matsu region of Taiwan.It is the primary and governing island for the Matsu Islands. It is also the largest of the islands. Most flights and boats will fly into Nangan. There are many things to see and most signs are in English, albeit some travelling requires guess and test.
The capital and location of the airport is Jieshou Village(Shanlong). Nioujiao Village (Fuxing), Fuao Village, Matsu Village, and Renai Village marks the other main villages. They are all tied to Central Blvd one way or another.
Since Nangan is the main island, there is massive military presence on all corners of the island. China is only a few miles off the coast and quite easy to see on a clear day. Nangan is also the main island, so travelling between islands is mainly via Nangan.
Also do not fear the roads. It may look like a sidewalk, but it is probably a road.
You can either fly using Uniair or take a boat from Keelung.
It is highly recommended you rent a scooter from the airport or Fuao harbor. Go to the Visitor Information and ask for help.
Also do pickup the English Backpackers Guide. It has highly detailed itineraries and somehow manages to provide an incredibly useful map.