Add Screen
Go to Features -> Digital Signage and tap New Screen in the top right.

Enter the screen code that appears on the DS screen when it is connected and powered on.

Give the screen a name. This name will be visible in the list of enabled screens, so make sure you come up with a good name that distinguishes the screen from the others. For example, "Entrance Screen" "Checkout Screen".

You can now select content for the screen if media files have already been uploaded, or you can choose to add content later.

After saving the new screen, it will appear in the overview of all active screens.

Upload content
To upload images or videos, tap Content.

Press Upload and drag the files in and press Save to upload the files.
You can now close the confirmation that the files have been uploaded. You can find the uploaded files under Content and then My Files.

Add content to the screen
Select the screen you want to update in the overview of all screens.

Click the Image, video or URL button and select the file you want to display on the screen.

Once the content is selected, it will appear in the screen overview. To accept the changes, press Save.

In the screen overview, you will now see that the screen has a green indicator showing that it is online and displaying content. Under the screen name, you will see which image, video or playlist is selected.

Create Playlist
To create playlists, tap Playlist and then Create Playlist.
Tap Add Content to select the content you want to add to the playlist. If you have already uploaded photos and videos before creating the playlist, you can find the uploaded files under Content and My Files.

You will now be able to add content to the playlist and choose how long the content should be before it advances to the next.

The playlist can be added to any screen you want.