I'd start with learning Hiragana and Katakana. After that grammar patterns and sentence structures? The vocabulary and kanji will come to you naturally, really. If it's translating you're concerned about, then I'd focus on learning the alphabet for now. I'd recommend using the Genki book series, it helped me out a lot.
Other than that, familiarize yourself with the language "naturally"? Listen to Japanese music, radio or watch Japanese drama or anime. That's what I've done and I can understand most things I hear or read now (ofc im far from fluent in speaking and writing). Also read raw manga. The kanji will be slightly difficult since there's many readings but you'll get used to it that you won't think twice while reading.
After I'm more familiar with the language and learnt the alphabet I'd start out by reading manga with furigana (they're little hiragana characters that show you how a kanji is read) and everytime I'd come across a kanji I don't know I'd write it down and familiarise myself with it. (I use Jisho.org to see stroke orders, sentence examples, and kanji readings and meanings. It's a really good Japanese-English dictionary c:) The manga I can remember at the top of my head with furigana is Kuroko no Basuke. I think it's good to read a raw manga with furigana that's already been translated (officially, if possible) and compare your own understanding of the text with the translation. I hope that made sense lol XD
If it's available to you, I'd recommend conversing with Japanese people. Since you're not exposed to the language, there's only so much you can learn on your own. And at most, people who have spent most of their time focusing on reading or listening, like myself, don't really progress much. My school had an exchange program where we got Japanese students and by conversing with them I learnt a lot of new sentence structures and vocabulary and I'd definitely recommend it. If not, like I mentioned before listening to a Japanese radio show or watching a Japanese show (or anything where they speak naturally, unlike anime or drama) should do the trick.
Sorry for babbling on, lol.
Anyway, best of luck learning Japanese! Personally, I think Japanese is a million times easier than korean so if you're easing your way through Korean I think you'll do just fine learning Japanese. Also, have patience. It's gonna take years at most. But it's worth it! ^^
ok thanks. this was really helpful
If I were wanting to scan and translate chapters for mangas. How would I need to do that? I'm not planning to do it right now since I am learning Korean right now but I do want to learn Japanese, how will I need to do it?