Basics:

The name of your Plug-In. One or more authors.

Homepage:

The homepage of your Plug-In. If you don't have a dedicated homepage, it is common to use your Github Repository. Your repository's git URL. Leave blank if you used your Github repository as homepage, or if your homepage redirects to a git URL.

License:

A License Identifier as found on SPDX. Common Licenses are GPL-3.0-or-later (used by Endless Sky) or CC-BY-SA-4.0 (used by the High DPI plugin).

Version:

How do you want to version your Plugin?

Github Release / git tag
Commit

The latest version of your Plug-In.

Descriptions:

A short description. Ideally less than 150 characters, must be less than 200. A description of arbitrary length.

Download URLs:

A URL to a direct .zip download. It's important that this URL be "versioned", i.e. contains your version, so it may only point to a download for this release and no other.
A URL to your plugin's icon, if any. Make sure this URL is versioned, just like the one above.