The best way to assign a podcast for your students is to create an assignment within Canvas with the assignment type "media recording."
When opening the assignment, Canvas will open a program within the interface for them to record audio with or without video. Here is a video tutorial.
Go to Google Slides and select an existing presentation or select New (+) to create one. Select the slide you want to add the audio file to then choose Insert > Audio from the toolbar. Choose your audio file (MP3, AAC, or WAV) from your Google Drive, then select Insert.
Formerly Flipgrid. Record using the audio option.