If you have created an account on the Directable website and installed the Directable app on a device such as a Fire TV stick, but no content is showing on the screen, most likely no Playlist has been selected.
To correct this, login to your Directable account, choose Screens>Edit Screen and make sure the appropriate Playlist is selected and then press Save. Your content should appear. When a new account is created, there will be a Default playlist generated automatically.
If you have built a Schedule for this Screen, make sure the appropriate Schedule is selected.