At some point in the dissertation process you will need to develop an outline of your work. In its most basic form this is usually just a listing of the chapters, or sometimes a more detailed chapter-by-chapter breakdown by section and sub-section. In some instances you may be asked for a preliminary plan as part of your research proposal in order to establish what your dissertation may look like in the future. Commonly though, your advisor/s may ask to see it as you gather your ideas before starting to write up.