In the text box, position your cursor where to embed the file.
Select Insert/Edit Movie button.
The HTML5 video properties dialog box will appear.
Select Browse Server.
The Entity Picker dialog box will appear.
Click the Upload file icon.
Select the Resources folder for the desired site. Select the Upload File icon to upload the mp3 file. If the file is already in the Resources folder, select the file and then choose OK.
Drop files or paste URLs or clipboard images.
Or click Select files.
The Upload files dialog box will appear.
Select the mp3 audio file to embed in the text box.
Once the audio file is located and selected, select Open to upload.
Select OK.
Once the file finishes uploading, it will show in the file directory listing and will be selected by default. Select OK to continue.
Select options.
Check the boxes for Responsive width and Show controls, then select OK.
View the embedded audio file in the editor.
The editing display will show the embedded audio player.