You'll notice that underneath your App Icon there are some options...
- Store Listing
- Pricing and Distribution
The green check indicates that the section has been completed, please ensure these are checked and that you have filled in all the details in Pricing and Distribution.
If you look near the top right of the screen you'll see a drop-down button that might currently says 'Draft'. Click that button and you should have an option to publish the app.
When that is done the app is LIVE but it may take a few hours to propagate across all the Play Servers.