
Hey, I am currently independently studying five languages - Spanish, Russian, German, Ukrainian, and French - it is very intense

I completely understand the struggle of finding resources to build a foundation, and moving forward, however, I have picked up kind of a strategy for how to approach languages, and this is what I found to be most efficient for myself:
1. Learn the absolute basics - this includes the alphabet, numbers, colors, basic conversation, etc., because it will be easier to understand context and apply other topics you learn when you know the basic vocabulary and such.
2. Memorize vocabulary - look up lists of vocabulary for the language you are studying online, anything from clothing articles to toiletries, the more, the better, I promise.
3. Pronouns - before you learn verbs and begin forming sentences, this is obviously necessary.
4. Verbs - memorize important verbs, make sure to mark the irregular ones, because they will be approached differently.
5. Conjugations - this will make up the majority of learning the actual language, because understanding how verbs apply to specific pronouns is extremely important when formulating sentences - make sure to learn the conjugations of both the irregular and regular verbs, as they will differ - make sure to understand the tenses that are within the conjugations (e.g. present, conditional, etc.)
6. Grammar - different languages have different grammar technicalities, however, there are several resources available on the internet - the most productive approach to grammar is definitely by practice, practice forming sentences with different pronouns and situations.
7. Adverbs, adjectives, etc - after covering the most essential parts of a language, you can begin to learn descriptive and more conversational vocabulary.
8. Practice, practice, practice - this is something that I have myself made a mistake in, and that is after mastering the language, I simply stopped bothering to practice it and review it, and now my Russian is substandard, and I must refresh several concepts
Please keep in mind that this is what works well for me, this may not be the ideal method for learning a language for you, this is just simply my approach, but I hope I helped a little bit