Answer:
First start by learning the alphabet you also need to learn the 3 basic writing system Higarana, Katakana, and Kanji
Next Practice the grammar of japanese
read these to help
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Practice Makes Perfect: Basic Japanese;
A Guide to Japanese Grammar by Tae Kim;
Japanese Hiragana & Katakana for Beginners.
Then Learn some Basic phrases like hello or hi and other basic phrases learn these and set a schedule for about 15 min every day to learn. You can also to talk native japanese people on trustable websites like
HelloTalk
LextTalk
MyLanguageExchange
and use the phrases you have learned so you can strengthen the japanese you have learned
Also Read Manga and Anime as you go on your journey it is both entertainable and also helps you learn you can spend your free time watching anime so it will help you learn some new words,including slang, and improve your listening skills.
That is my advise to you i speak a little japanese and have some experience
you could do this or
Hire a tutor for japanese
or
Watch a video about it
or
Read a Article about learning it
Hope this helped