Question: How do I structure chapters for a long story?Answer:
That's a pretty big question, since not every chapter will be structured the same way.
However, it is helpful to think about chapters in terms of events. Every event starts somewhere, with an intent or inciting incident. That leads to complications and opposing forces, followed by a decisive action or decision, and finally a result that leads into the next event.
Of course, some chapters will contain more than one event, if the events are small. Big events will probably need a chapter to themselves.
When your chapter contains more than one event, I recommend a technique (which J.K. Rowling uses a lot) which is to make sure each chapter ends on a different emotional tone than it starts. So even if the events in a chapter are part of different subplots, the reader still is being taken on an emotional roller coaster that will propel him forward.