This app was mentioned in 3 comments, with an average of 1.67 upvotes
just double check. but i'm pretty sure its white for the basics. then pink for practice/exercises for that topic.
from memory, the 'real learning' starts at chapter 3. sorry its a bit all over the shop. i did the classes and even then it was still a bit confusing. but if you just go chapter for chapter, you'll work it out.
BUT. i'm glad you mentioned hiragana and katakana.
because the japan foundation have REALLY REALLY good apps for learning them
https://play.google.com/store/apps/details?id=jp.jfkc.HiraganaMemoryHintApp.En
https://play.google.com/store/apps/details?id=jp.jfkc.KatakanaMemoryHintApp.En
ultimately, what you'll find is that you just need to start. and be consistent. 5 minutes a day is better than 0 minutes a day.
once you start it'll start making sense about the structure and going forward and what works best for you.
just start chipping away. and dont forget to have fun. seriously. if you started doing 5 minutes a day, consistently, and watching a few episodes of a japanese tv show a week, you'll be ahead of 95% of japanese learners, the most of who will do a powerful 3 hours one week, then never do anything for the rest of the year lol
Do you have a plan for how to learn yet? Are you going to use a certain course or something like that?
I'm a total beginner too, but here's what I've currently stuck with (as a person who, right now, is learning 100% by myself, at home):
You need to learn hiragana (there are great apps with memory hints for this - Android / iOS )
Similar apps are available for the katakana ( iOS / Android ). Your goal is to be able to draw the kana without having to look it up. Remember that words of foreign origin are written in katakana, but your priority at the beginning should be nailing hiragana. Generally, don't touch kanji yet unless you're really curious.
I've generally had the problem of "what do I do now?" at this point, but it seems that when it comes to interactive "coursebooks" that don't cost a fortune (or subscription, I kinda hate subscriptions), Human Japanese is a good bet. It's available on almost all platforms (Windows, Mac, iOS, Android) and starts with the assumption that you know nothing about the language. What's important here, is:
It has animations which show the stroke order for the kana (which is quite important)
It has included pronounciation for all of the phrases and words
It's written in an easy-to-understand and often humorous style
It cycles back and forth between grammar and vocabulary
It includes quizzes and reviews for improving your memory of the things you learn
So far I'm pretty happy with the program, I'm really not sure what I'd do without it (how do I start?).
And... just remember to have fun with the language. Only learn if you find it to be something that you want to do, otherwise it's going to go terribly slow for you. Good luck!
My wife had me try this app when learning the alphabet. There is one for katakana and Kanji as well:
https://play.google.com/store/apps/details?id=jp.jfkc.HiraganaMemoryHintApp.En