Having basic knowledge of the alphabets is not enough to go on. So a basic grammar book is a must. Check out a deal reading another book about the history and development of the language. It is quite to my goûte for I am Chinese. Very helpful. Now, check my out the second book about grammar, though quite classic, 1914 ed. by Japanese researcher, may be close enough to after war re-organization of the language. There is the grammar part too.
Review: after finished going through the first book, briefly on subjects more helpful to the understanding of Korean language; I found the historical development of the language is important but lacks the more directly related sino-kuguryu interactions; such as wars, battles, immigrants, exile movements, colonization etc, subjects like these! Some pieces of losing research facts are: Sung dynasty inventions of papers plus printing ; it's immigration from central china; chinese and hence inclusive locales' literatures modes and changes; these may be some others I think explain and can give more insights into the causes and short/long terms development of the language. See that I quite like Sung poems, proesies. They bear very magical rythmes, kind of aesthetical! And this much for the first reading!