Sections are a way for you to divide the External Survey into smaller, more manageable parts. Once the External Survey has been created, you are ready to start adding Sections, after which you will be able to add questions.
In the External Surveys tool, click on the name of the External Survey that you would like to add Sections to. After that, you should see a list of the names of any Sections that currently exist in that survey. Click the New Section button towards the top of the page to add a new Section to that survey.
Here, you can simply enter the Name you would like to give to the section.
When you are ready, click Save and you will be able to add more Sections, or start adding Questions to your Sections.