You can choose a background of the page by deselecting everything and looking for the background section in the object panel to the right. You can position the background here in a few ways. You can set it to proportional, cover and stretch. The most used setting is “Cover” because it will always cover the canvas. “Proportional” scales the image to fit inside the canvas but can show whitespace around it. “Stretch” stretches an image to fit inside the canvas.
In Maglr Pro you can add two types of audio :
From the default page settings you can select a MP3 file. When the page starts the background music will automatically play. A visitor can mute the sound in the menu bar. When a video starts the background mutes, when the video ends the background start to play again.