The Course Overview on Campus Block is the main block you see in the middle when you log into your Moodle dashboard.
This block allows you to easily sort your courses by category.
To change the default category view, click on the drop down arrow under Parent Category:
This will list all courses contained in that category and will remain the default view the next time you log into Moodle.
To hide a course from this view:
Click the eyeball icon next to the course you wish to hide from this view. NOTE: this will not hide the course from students, just from this block. To make the course inaccessible to students, see Hide Course.