If the lesson audio file is larger than 20MB, then it likely needs to be reduced to work properly on the website.
If you have access to the MP4 video file then you should use it to make a new, smaller audio file.
These instructions are for reducing the size of a MP3 audio file. Although the quality of the audio will be compromised, sometimes it’s all we got.
Install Audacity: http://www.audacityteam.org/download/
Install LAME for MP3 encoding:
Import audio file: Open Audacity program, Click File, Click Import, Click Audio, Select file and it will load.
Export MP3: Click Export Audio, Select where to save it, Save as Type: MP3, Format Options: Variable, (9, 45-84 kbps smaller files), Fast, Joint Stereo. Metadata Tags should be correct (if not see below ) so click OK. A window showing progress will appear. When finished check the size of the file by right clicking the file and in the General Properties tab the size will hopefully be less than 20MB.
If Metadata is not filled in, then add as follows: Artist Name- W. Mark Lanier, Year- 2017, Genre- Bible Study, Comments- © 2017 Mark Lanier
Add the audio file to the lesson shell.