You can follow the following steps to self-study radio drama post-production:

1. Learn basic knowledge: Understand the basic concepts and processes of radio drama post-production, including sound collection, editing, sound effects, mixing Sound etc.

2. Choose tools and software: Choose software suitable for radio drama post-production, such as Audacity, Adobe Audition, Final Cut Pro, etc., and learn how to use these tools.

3. Learn sound design: Understand the art and design of sound, including sound collection, adding sound effects, mixing techniques, etc.

4. Master script analysis skills: Learn how to analyze scripts and understand the characters, plots, scenes and other elements in order to perform better in post-production.

5. Learn sound editing skills: Learn how to edit and process sounds, such as editing, adjusting volume, adding reverberation, etc.

6. Collection of sound effects and background music: Accumulate a large number of sound effects and background music for use in post-production of radio dramas.

7. Practical exercises: Continuously improve your post-production skills through practice. You can find some scripts and sound materials to practice, and continue to try and improve.

8. Participate in exchanges and learning: Participate in some communication and learning activities for radio drama post-production, interact and learn with other post-production staff, and share experiences and skills.

Finally, it requires patience, perseverance and persistent learning and practice to continuously improve your skills and levels.