You can upload and use your media with audio as shown below:
Step 1: Select ‘Edit’, then head over to ‘Media’.
Next, click on 'Uploaded Media'.
Step 2: Click "Upload media" to add your video or image. This will allow you to replace any existing media with your own.
After adding your media, go to Media properties to increase or adjust the audio volume.
Click on Proceed and save changes once done!