There is not a built-in feature to emulate a binder on Google Docs, but you can achieve a similar effect by nesting documents inside of a master document. To do this, create a new Google Doc and title it "Binder." Then, create a new Google Doc for each section or topic you want to include in your binder, and nest those docs inside of the "Binder" doc. To nest a document, click "Insert" > "File" and select the document you want to nest.
Here's a video tutorial that shows how to nest documents in a Google Doc: https://www.youtube.com/watch?v=GxgEDyodMJc.
