Here are two guides:
the one I used when I started --
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;
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Basically the order you'll be learning ideally should be like this
katakana/hiragana -> grammar -> kanji
To start with the first, here's a very useful link that will help you remember kana
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In short, it's a memorization game. It comes down to this, when you're able to write all checked kanas without making a mistake, check another row. Don't despair if it's hard at first, people usually learn these alphabets not overnight, but in a week or so.
When it comes to grammar, I can't recommend Tae Kim's book enough. Here's a PDF version of it
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I bought it on amazon, I believe it's still available there, if you want a copy.
To learn kanji, you will need to install a program called anki. Practically everything essential is written here
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, but I'll just add that there's is an alternative way to learn kanji called heisig method. To sum it up, instead of remembering kanjis you'll be learning radicals these kanjis consist of. It's a pretty controversial method, and from my own experience without his book or at least your own notes it'll be hard to learn kanji using it. Anyways, start off with Core 4k/6k deck recommended in the guide, and then if you feel like it try Heisig method. I think there's an anki deck for it too.
If you have any questions, shoot (here or in PMs).