In order to add an audio file to Movavi Clips project, please take the following steps:

1) Open your project in Movavi Clips app and tap on the“Audio” icon. That is the first one right above the video track:

2) Tap on the “+” icon, it will redirect you to the tab "Add music":

There, you can select the music from either your phone gallery or the Movavi Clips built-in library:

If you cannot find your music here, please check this article.

3) Select the audio and tap 'Select'. 

Thus, the music will be added to the timeline: