Thank you! Yes I do not speak and understand Vietnamese. I learned a few Kanji but just by memory and recognition though I can't write them so there are times I don't know if those are the same Kanji'sI assume you don't speak Vietnamese, so you may want to check these out:
Basically it helps you memorize words by repetitive memory drilling. The most basic method is recognition: you input a word with a clue in a way that whenever you are given that clue, you can remember the word easily. With enough repetitions, the words you input will ingrain in your brain, and this method is useful in learning kanji since you need to memorize as many words in the active vocabulary of Japanese language as possible.