How do I turn my business idea into an actual plan?

The idea is alive in your head, and the moment you try to make it a plan it turns into a mountain. That overwhelm is not a sign the idea is bad or that you are not capable. It is a sign you are trying to see the whole thing at once, which no one can do. A business plan is not a fat document. It is answers to a few plain questions. What are you selling? Who is it for? How will they find you? What will it cost and what will you charge? That is most of it. When you write it as answers instead of an essay, the mountain flattens into a list you can actually climb. Today, answer just the first question in one or two sentences: what exactly are you offering, and to whom. Do not move on until that is clear and simple. Everything else in the plan hangs off that one answer, and once it is written, the rest comes far easier.