You can download and install plug-ins from the dedicated forum created by the Paint.NET developers.
Support forum: http://forums.getpaint.net/index.php?/forum/7-plugins-publishing-only/
This is the standard and the simplest method of plugin installation:
- Download the plug-in in the ZIP/RAR format.
- Extract it to a location of choice, then copy its contents.
- Navigate to where the Paint.Net is installed and paste the files in the correct directory (most used is Effects folder).
- Restart Paint.NET and the plugins will be available for usage.
If you can't see them, navigate to the installation folder and right click the DLL files, then use Unblock.