How to make your Moodle course 'Available' to students:

Once you have logged into Moodle and are in the course you want to make available to students locate the Administration block
adm blk

Click on Settings
settings

Under the Availability section click on the pull-down menu and select "This course is available to students"
avail sect

Scroll to the bottom of the page and click on the Save changes button at the bottom of the page
save changes

Your course is now available to your registered students.