To publish your mod to Steam Workshop, just open your mod information via the Developer Tools sidebar. To do this, click the right pointing triangle beneath the thumbnail image at the top, and then choose your mod. If you're running the Steam version of Mannequin, you should see
Upload to Steam Workshop button. Click that, wait for the upload process to be completed, and you're done!
After your mod is successfully uploaded, another file will be created inside your mod's folder:
steam_workshopid.txt. This file contains your mod's Steam Workshop ID, and as long as this file is present, the
Upload to Steam Workshop button will be replaced by
Update Steam Workshop Entry.
To publish your mod to itch.io, just do it the usual way like you do when you're uploading a game. We can't really tell you what is right or wrong because itch.io does not have any strict guidelines regarding this. For our example mods that is already live on itch.io, we're picking the
Game mods category,
Downloadable kind of project and added
mannequin tag in its project information.