In simple words, a module is nothing but a main topic and a sub-module is a chapter/lesson under the Main Topic.
To create a module,
Head to Course Builder, under Course Creation,
Choose the tab Create Module.
Choose the Course from the menu, to which the module has to be added.
Click on Add New Module & provide a name for the module.
To change the module position, you can assign a number of your choice, to each one.
Pro Tip: You can unpublish a course, if you are working on it and don't want it to be visible to students. Once finished, you can publish it again.
You can also edit the name of the module, by clicking on the edit button of the particular module.
You can Preview your Module & Sub-Modules, by clicking on the Preview Button on the right-hand side.
To create a sub-module,
Under the Create Modules Tab, you can view all the created modules.
Click on Add Sub-module for your required Module.
Enter a title for your sub-module. You can either add a video URL or upload a video or embed a video iframe.
You can also add an attachment and add an overview of the sub-module.
To edit the sub-modules,
Click on the Edit Button, under actions.
You can change the sub-module position by assigning a number of your choice.
You can edit the video, overview & attachments, by clicking on the edit button.
To delete a sub-module, click on the delete button on the right-hand corner of the sub-module's row.
Pro tip: You can assign tests & assignments directly to a particular sub-module, by clicking on Add Test & Add Assignment.