How do I add extra information on top of the syllabus details that come from CMS (Curriculum Management System)?

The recommended approach is to create additional Canvas 'Pages'. Canvas Pages function like webpages and can include multimedia content such as images and videos. You may also set any Page as the 'Front Page' of your Canvas course.

Additional resource: https://community.canvaslms.com/t5/Instructor-Guide/How-do-I-add-a-module/ta-p/1151