Sorry for the late response, it has been a really busy day for me!
Bingo! I agree that even though FCC is great when it has given a guide of what topic/elements needed to be learned, I feel their exercises don’t go into the depth of what they are teaching. However, other platforms are the same (especially if they are free)
The thing is to find someone to teach you thoroughly and guide you as you do it is going to be a tricky one to get especially at free cost. However, if you feel this is the right way of learning, I could suggest to google “coding mentor for free” and see what comes up?
However, personally myself, I learn much better through video courses where not only they teach you what certain codes do but they provide doing a project (like creating a web page for food recipes for example) where the instructor will create it and explain what and why they have done that way. You also meant to copy and follow as it goes along so it feels like you are in the real-world environment. Normally, they tell you what code editor is recommended and how to set up a project folder, etc. (Btw, I don’t care what code editor is recommended, so far Atom is my favorite)
My favorite platform for learning is Udemy. Now, before you say it is not free, they do actually free courses too (just filter it in the search), and I would normally search for courses that do projects as well. For example, like this course. Now, I cannot guarantee you that all courses on it are helpful, so try to find a course where it has good ratings and reviews and checks the syllabus of learning as well.
I know you said you are not interested to pay, but in case you ever changed your mind, they do have amazing courses but my tip is ONLY to buy them when they do sale periods (like they are doing now where most courses are £9.99 reduced from normally £199.99).
One more thing, even the greatest course or platform you might struggle to understand a certain code at one point, when you do, look at further online resources such as w3school or blog posts about it. They tend to be very helpful.
Okay, sorry this is long but I do hope this will be helpful to you and also if you have any questions, forums are there to answer them, oh and you are welcome to ask me as well
EDIT: Oh I also forgotten to mention, even if you do learn on other platforms, this is not to say to give up FCC! Like myself, when I am on the topic (i.e responsive design) I would learn it elsewhere then come back to apply my knowledge