(you might have wanted a Japanese person's answer but...) I would recommend starting by learning the alphabets (especially if you're not used to hearing the language) first hiragana, then katakana. Find a site or app that lets you listen to the sounds so you'll get a good feel for how things are pronounced, even when you see them in Romaji. After that, start a small vocabulary- you might want to look up something like '100 most used Japanese words' or 'basic japanese verb list' and then try to learn those after that, you should have a starting point- next I would work on grammar before building up vocab anymore. My favorite source for this is this website: http://ww8.tiki.ne.jp/~tmath/language/jpverbs/index.htm I would suggest going through this whole guide. When you have a good understanding of how the language is constructed- you should be able to pick up on vocabulary pretty naturally. Try to keep listening to Japanese regularly while learning- both with English translations and without. You can do this by either watching anime, youtube videos, or various other resources. --- hopefully this helps- I wont say anything more for now since I don't want to over-inform haha, but if you want there are many more resources and suggestions I can give you, if you want them just let me know :)

start learning hiragana and katakana

Oh wow, sorry I thought you were a native English speaker (guess that's a good thing though right? haha) Sorry if my paragraph was too complicated, I would have tried to speak more simply if I had known. Also the links I gave probably won't help since they're all in English ^^; sorry, my bad.