As a student of Japanese it is very important for you to learn the Japanese writing system. The advantages of learning to read Japanese are well worth the study time. Learning to read Japanese involves learning and memorizing the two syallbaries, Hiragana and Katakana, and then about 1000 to 2000 Kanji.
Consider Hiragana as the baby of the three. It is the first syllabary Japanese learn. It is primarily used to write out things for which there are no kanji, such as verb endings and grammatical elements such as prepositions. It is also used for writing out things for which there are kanji but which do not warrant kanji to be used, such as some simple words, or writing out names without kanji. For example, my wife’s name is normally written in Kanji, but her parents choose to have her name written in hiragana instead of Kanji. So always writes her name in Hiragana.

Katakana is like the teenager constantly changing with the modern culture. It has two purposes. The main role of katakana is writing out foreign-derived words often referred to as load words which have been integrated into the Japanese language. The number or loan words is growing rapidly. The second purpose of katakana is to put emphasis on words, similar to the western use of italics, underlines or asterisks. This why you will find a lot of Japanese written in Katakana in manga. Katakana in manga is often used to express anger or surprise.

Kanji, the old, traditional and meaningful script. The wise half Japanese, half Chinese Grand Daddy. Most students of Japanese know that the bulk of Japanese script is not actually Chinese in origin. And the Japanese kanji that are in use today are merely a subset of a vast number of kanji that were in use up to less than a century ago. Ths problem with Kanji is in the “readings”. There are two readings for Japanese Kanji; one that comes from classical spoken Japanese called kunyomi and readings that come from classical Chinese are called onyomi.
The problem with these readings is that it is not always clear when to use which reading. There are no rules that state that a kanji is read in a particular way when used on its own, or when part of a word. The only real way to make sure you are using the right reading for a kanji when encountered in a context that
you had not seen it in before, is to look it up – while sometimes one can guess whether a kunyomi or onyomi is used, it is typically impossible to be certain.