The best way to learn is a language is by listening to it a lot, get a lot of input. You shouldn't understand it yet. Avoid subtitles. It's tedious. I didn't think I was making progress. Little by little you understand words, phrases, sentences and conversations.
Don't use a textbook or course as the main way to learn. You may only use them in ADDITION to listening.
I am a native Dutch speaker. I've learned English. I don't know all of English grammar rules. Most of them are learned by seeing and hearing a ton of it. The brain will figure out patterns, that's what it's good at.
Dutch and English are very closely related. Both are Germanic languages with a touch of Romance language added. It's relatively easy.
After struggling with Japanese, I'm using this input method. I can't understand what these podcasts are talking about. I need to think too much about the grammar. It's not intuitive yet. I need to listen more. I need more input.