Uh… do you happen to have a textbook? It’s true that grammar only feels useful/fulfilling when you have vocabulary to use with it, but you often won’t be able to acquire new vocabulary in context without grammatical knowledge. Textbooks help you to acquire both at the same time, ideally with a decent amount of context so that what you learn is meaningful. If you don’t have a textbook or don’t intend to get one… well, you can try to cobble together a free/almost free DIY Japanese learning system. I don’t recommend it, because progress will be slow and probably painful, but it might still work. (It could even be better than a boring textbook, so who knows?)
For grammar, the closest things to textbooks on the internet are Tae Kim’s Guide to Japanese and Imabi. If you want lots of information on a particular structure in an easy-to-understand article full of example sentences (which is probably going to be good for your vocabulary as well), then you might want to check out Maggie Sensei’s site. The easiest way to find a specific article is to search ‘[grammatical structure] maggie sensei’. If she’s written something about it, it should show up.
As for acquiring vocabulary… in my opinion, you need a source for new words, and you need to practice output in some way. It’s not about disproving the ‘input hypothesis’ or ‘output makes perfect’ or whatnot… it’s just that output is retrieval practice, which is always good for memory. How can you do this on your own? For input… there are free online courses from NHK, along with NHK News Web Easy, which is for slightly more advanced beginners. Duolingo is another way you can pick up new words. (Side note: I hate Duolingo’s approach with a passion, even though it’s a good way to start a new language if you want to do it for free. Sure, it’s about repetition and translation exercises, turning it into a glorified flashcard system… but it’s super rigid and offers you no context whatsoever. The strongest proof of this is how much users complain in the comment section for each sentence, asking why their perfectly reasonable translation is ‘wrong’. However, precisely because it’s a glorified set of flashcards, you can use it for vocabulary if you can tolerate the mechanical nature of the system.) Other helpful input sources are podcasts aimed at learners, like things from JapanesePod101 and Nihongo con Teppei (or something like that). For output/retrieval practice, I strongly suggest you write Japanese characters (kana and kanji) after learning the correct stroke order. It’s not just about deciphering weird signs, though it does help with that: it’s about using muscle memory to help your brain absorb new structures. You can try something like glancing at a vocabulary word and reading it aloud before covering it, repeating its pronunciation, and writing it in kana before writing it with kanji (if it has a kanji form).
More motivating ways for you to pick up new words and practise output will come up once you know a little grammar: you can try reading children’s books or watching anime (with basic grammatical knowledge, you’ll be able to pick up simple catchphrases, at the least). You can also join book clubs on the forums. I’m personally part of a group on the forums that translates simple NHK articles in order to understand them, with more advanced members helping those with less experience. (It’s here: NHK Easy News reading group) We used to tackle a manga as well, but that’s on hiatus. All these attempts to understand Japanese sentences and to use the words you’ve acquired will help you to figure all these structures out and understand what’s going on.
As a final thought, I understand that it’s not easy to have to deal with technical terms when you’re not used to handling them in your native language: picking up my third language, French, was confusing at first because I didn’t know what all the technical terms meant. However, to learn Japanese, you need to have at least a rudimentary understanding of these terms. That means you need to find a resource that clearly explains these concepts, or which at least gives you their equivalents in English. The reason these concepts are important is because Japanese tends to signal changes in function/role using suffixes and particles that are tagged onto the end of an existing word or sentence, and so you’ll need to be able to decode these things. A few weeks ago, I caught myself mentally changing the class/type of a verb in my head while watching an anime as I heard the suffix change. As for how to take apart Japanese sentences… think of onions. Here’s a link to a post in which I take apart a fairly complicated-looking sentence in order to illustrate what I mean by the idea that Japanese starts from a core and adds layers of meaning to it.
Finally, all the best! I strongly believe that everyone on these forums will be willing to help you and give you whatever advice they can. 