Download the blender-hdri-gen.zip from Releases and install it using Blender's built-in add-on installer, located in Edit > Preferences > Add-ons > Install... and select the .zip archive. Afterwards ...

This Blender add-on is under development. While it can be used if you find it helpful it might be bugged and not easy to install. This add-on doesn't support multiple exports yet. Select one object ...