1) Open Apple mail and select the email you would like to bring into PM.
2) Simply drag and drop into the desired quadrant!
The subject line of the email will become the name of the task, and email content will be shown in Notes. Any attachments will appear in the files section.
If you want to access the original email, just double click on the task.
*Please note that when dragging and dropping emails, only the individual email is brought into your Priority Matrix, not the entire thread.