It’s easy…
1 ExporT
Once you’ve build your project in MSFS, copy over the Package folder (<Project_folder>Packages<Project_Name>) with the correct project name to a secondary folder somewhere.
Make sure you fill in the creator and title fields in the Manifest.json file!
You can add extra stuff such as screenshots and ReadMe files into the secondary folder, these will be ignored by Package Manager.
The only important part is manifest.json and the correct relative location of all the required Package files and folders.
2 Compress
Using your favorite file compression program (WinRAR, 7zip, WinZip,…) , compress that secondary folder that contains your MSFS package data, ReadMe and screenshots and Compress it.
Package Manager is designed to be able to handle .zip .rar and .7z files. As long as they are not password protected.
Don’t compress your MSFS package folder before!
Package Manager cannot handle the compressed file containing another compressed file that contains the MSFS package. In this case Package Manager will show a warning to the user, and will ignore the file.
3 UPLOAD
Upload that .zip, .rar or .7z file to the Flight Simulator File Library of your choice.
Once a user downloads your file, it can be immediately dropped into Package Manager and installed directly to their Community folder with 0 effort!
Structure
It’s important to maintain the structure of the MSFS exported package within your compressed file. Do not alter, rename these files and folder, just make sure they’re included in your compressed File. You can put the package folder in another Folder within your compressed file without issue.