Koreans almost universally have three names, the family name or surname placed first and a name identifying the generation, ordinarily the same for all male members of a clan, alternating in each generation to second or third place with the given or personal name.
Some Koreans when writhing their name in the Western or Roman alphabet will invert the word order and place the family name last, as Westerners do. This can lead to confusion, however, since many Occidentals know about the traditional word order of Oriental names and will still identify the family name by reinverting the inverted order.
For instance, my name 
can
be written by roman alphabet like Kang Young Tae and these word
order also can be inverted like Young Tae Kang, Young-tae Kang or Youngtae
Kang as Westerners do. In any case, Kang is Family name, Young
is the name identifying the generation of male member in the same clan
and Tae is personal name. But generally Young Tae is regarded
as given name.
Keeping people's name straight can be confusing in Korea, because Koreans have so few family names at their supposal. A good rule of thumb to bear in mind is that only a few family names cover the vast majority of all Koreans. People named with Kim, Lee, Park are well over half the people in Korea. If you see the names Kim, Lee, Park, Chung, Chang, Cho, Choi, Yu, Yun, Kang, Han, Ko, Lim, Shin, Oh, etc., you can be fairly sure that it is the family name, whether it appears as the first or third word in the sequence.
Most of Korean Amateur station use their family name because all most all Korean family names have only one vowel sound and are very simple and easy to copy. But you have to be aware that the romanization of Korean (using ABCs to write out Korean words) poses a special problem. There are two or more ways of spelling some words, and it often seems that each Korean has his or her own way of romanizing language especially their name or address because of variations in pronunciation. Lee, for example is also spelled as Li, Yi, and Rhee. And in Korea, family names are so important that women do not change them even when they get married .