You can have some summary text about this lecture here. The .mp3 url can just be added directly to the WP content field just like this text and it will automatically convert it to the audio player. If you want to add a direct link to the mp3 you can do that as well. Also, I assume this would be in a Media Post and to separate it from other content you may want to assign it ‘audio’ and/or ‘lecture’ tags.
