Read the Notes for developers at the top of the
Index of plugins thread.
You'll need to edit the opening post of this thread so that conforms to the layout and content of other plugin threads - use one of the other Metadata Download plugin's first post as a guide - main thing is that the plugin zip must be attached to the first post.
The next release of calibre will be released soon. It requires adjustments to be made to plugin code to make them python 3 compatible, see the relevant sticky threads at the top of this forum for details.
When you're ready to roll, PM me or one of the other mods with the details you want in the index.
BR