Once you have created your course, and hit the publish button, it would be visible in your course Store page. On both your website as well as apps, depending upon which plan are you on.
However, if you have published your course, but it is still not available in the Course Store of your apps, here is how you can rectify it:
Go to the Course which you want to publish in the Course Store & click on Details.
Now select "Pricing" & check "List course for sale". If it's marked "none", or just checked on "website", it has not been published on Android or iOS apps.
To make sure your course is visible on your apps as well, you need to check the "Android" & "iOS" boxes individually.
After checking the boxes, click on "submit" to save the changes.
Now, go back to your Apps' Course Store, the course will be published.