How do I structure a whole story from start to finish?

You can tell a story in the small, a good moment, a vivid scene. But holding a whole narrative together from beginning to end still trips you. That is a real and common wall. Telling a piece is one skill; building the whole arc so it carries a listener the whole way is another, and it takes a bit of scaffolding to learn. Underneath most whole stories is a simple bone structure. Something is a certain way. Then something changes or goes wrong. Someone tries to deal with it, struggles, and by the end things have shifted, for better or worse. Beginning, middle, end are not just an order; they are a change. If nothing changes from start to finish, you have moments but not yet a story. So before you build the whole thing, name three things: where it starts, what changes, and where it lands. Just those three, in a sentence or two. That skeleton keeps you from getting lost in the middle. Then fill it in, always asking whether each part moves you toward that ending. Structure is not a cage; it is the spine that lets the whole story stand. Give it a spine, and the rest holds together.