How to split a document content in various sections

I have used doc.getSections() function in my application but problem is that it is putting whole content in a single section. My document is very big but doc.getSections() is giving only single section . I have attached my document here for your reference. Please suggest me how can I split up the content in different different sections ?

Thanks for your request. Please see the following links to learn more about Sections in word documents.
I hope this could help you.
Best regards.