Before getting started on anything, it’s important to know what you want to achieve through this learning experience. Do you want to understand the language and be able to read and write? Or do you just want to learn conversational Japanese? Different methods should be employed based on the outcome you hope to achieve.
For example, if you wish to focus on reading and writing, you might want to get a textbook such as Genki, Minna no Nihongo, etc. Learning how to read and write basic characters of the Hiragana and Katakana chart will be foundational before moving on to grammar points and picking up a few Kanji characters along the way. I once took a preparatory course for JLPT N1 (Japanese Language Proficiency Test) and the focus was mainly on learning words and reading comprehension passages. I learnt a lot of grammar and can read more kanji characters than before, but because I hardly got to practice speaking the language, do find myself at a loss for words at times even though I completely understand a question posed to me in Japanese.
On the other hand, while still beneficial to learn Hiragana and Katakana, if you want to learn conversational Japanese you have the option of listening to audio lessons in Japanese. Japanese language schools also offer conversational classes which are likely less intense than one preparing you for tests like the JLPT. You can also look for conversation groups around your area (usually called “Nomikai”) where native speakers gather to exchange language knowledge e.g. native Japanese will come to learn English, and native English speakers will come to learn Japanese.
Of course at the end of the day, you will have to learn a bit of everything. However, not all resources are created equal. Where one textbook may give you comprehensive knowledge on grammar, another may prove more useful in giving you the tools needed to carry a simple conversation. It’s important to remember what your true objectives are because each resource often provides different materials for a specific outcome. Bearing your main objective in mind, do some research to find the learning method most suited for you.