on start of layout (add another condition) > system > compare two values > LayoutName = "your_layout_name"
*** audio > play > select your audio, set it looping, give it a tag (BGM for example)
on start of layout (add another condition) > system > compare two values > LayoutName = "your_layout_name"
(add another condition) > audio > is tag playing > "your_tag_name"
*** audio > play