In the course creation process, and after choosing to manually create your content, you clicked on the "Add Button". Follow these steps:
Click on "Text"
Enter the title of the paragraph at the top
Write the paragraph for your students to learn
Highlight a word if you want to add to it a definition
Click on "Add Definition"
Drag the toggle on the right side in the "Settings" to assign to the paragraph an estimated time to read
Click on "Save" to save the text or "Close" to discard the changes