# 9.1. OLX Course Building Blocks¶

Before you begin using OLX (open learning XML) to set up a course, you should understand the building blocks of an edX course.

## 9.1.1. Courseware¶

Courseware is the main content of your course and consists mainly of lessons and assessments. The following list describes how courseware is organized in OLX.

• Course chapters are at the top level of your course and typically represent a time period. In Studio, chapters are called sections.
• A chapter contains one or more children which correspond to top-level pages in the course. In Studio, these are called ‘subsections’ and are currently restricted to sequential elements at this level. OLX supports any XBlock at this level.
• Courses are composed of structural elements, such as sequential and vertical, and leaf-nodes or content elements, such as html or problem. Studio has a fixed hierarchy where children of sequential elements are vertical elements (called units), and children of vertical elements are leaf elements (called modules).

## 9.1.2. Supplemental Course Content¶

In addition to the courseware described above, you course can contain supplemental content, such as textbooks, custom pages, and files. The following list describes the types of supported content.

• Course assets are any supplemental files you use in your course, such as a syllabus as a PDF file or an image that appears in an HTML component. For more information, see Course Assets.