This is a really hard question to answer because we can't be too specific without knowing your personal learning style. In terms of order for learning the writing system, it's definitely best to do hiragana, then katakana, then start working on kanji. Though really if you start learning a couple kanji here and there right from the beginning that won't be terrible. You can learn the writing system while starting with some grammar and vocab but most materials move past using romaji pretty quickly, to using only the actual Japanese writing system. Anyway, other than that just make sure to set yourself specific (attainable! aka not "becoming fluent") goal, so that you can keep yourself motivated and feel good when you reach each small goal. Learning hiragana in xx amount of time is a good one to start with.

by memorizing JLPT wordlists