Students cannot access a course in Canvas until it's published. If your course is unpublished, you will see a bar across the screen with the text “THIS COURSE IS UNPUBLISHED". Only teachers can see this course until it is published.
To publish your course you have to click the 'Publish' button on the top right corner of your screen.
The button will turn green.
You will also see a massage confirming that your course has been published.
Enrolled students will be able to participate in your course and see its content 1 week before the semester starts. After the semester ends, your course will be in a read-only state for students.
Please remember that different elements in your course (Assignments, Discussions, Pages, ect.) will also need to be published when they are ready to be seen. Otherwise they will be invisible to students.
Whenever you see a cloud icon remember that a gray cloud icon means unpublished.
A green icon means published.
You can toggle those back and forth.
A quick way to make sure everything you want visible is published is go into 'Student View'.