1. Make sure the AVIF to PNG plugin installed inside your bubble.io app
2. There is only one action, called Convert AVIF which converts the AVIF file to PNG

3. In order to use this server side action, make sure you have access to a AVIF file you want to convert to PNG.

4. Inside the action you need to fill in several parameters:
4.1 website_home_url: Your website home url, it should look something like: https://[id_of_your_app].bubbleapps.io/version-[appVersion]/
4.2 privatefile: Make sure you set this to yes if you want your file to be private
4.3 file: The actual file you want to convert. Make sure you add 'http:' before the file URL
4.4 filename: Desired name of the file

5. After this action runs you will receive the new image URL in the new_image_url parameter

In this editor you can see a correct setup of this plugin:
https://bubble.io/page?id=base64-to-image-demo&test_plugin=1767184688522x607270302432100400_current&tab=Design&name=avif_to_png&type=page&elements=bTHEh