First go to click on the blue plus button on the left sidebar of your Chalkup screen and choose "New Material" in the menu.
Next, upload the file or add the link/video that you would like to share with your course.
Finally, select the courses you would like to where you would like to post the resources. You can now select multiple courses at the same time. When you're ready to post the resources, select the "Share" button and you'll be all set to go!
When you select multiple courses at the same time and share, Chalkup will make a copy of the file automatically and post it as a Material in your 'Materials' tab of your course. Students will be notified and everyone will have access to view.