How to publish a saved World

1. Launch Space Engineers
2. Go to main menu, click “Load World”
3. Select a world you want to publish
4. Click “Publish”, pick your tags and destination (steam workshop and/or mod.io)
5. Wait until the world gets uploaded
   
6. If you chose so, Steam Overlay will open up and you can manage the workshop item from there
7. Use Steam Workshop Owner Controls menu to further manage your workshop item (adding video/images, changing visibility, editing the description)

How to publish a Blueprint

1. Launch Space Engineers
2. Go to main menu, click “Load World”
3. Select a world, load into it and point a cursor on a grid you want to upload
4. Press CTRL+B. Blueprint menu will open with the chosen grid saved as a blueprint. (or optionally open the Blueprint Menu with F10)
5. Here you can manage your blueprint (edit the name, description, take a screenshot, etc.)
6. Click “Publish”, pick your tags and destination (steam workshop and/or mod.io)
7. Wait until the world gets uploaded
8. If you chose so, Steam Overlay will open up and you can manage the workshop item from there
9. Use Steam Workshop Owner Controls menu to further manage your workshop item (adding video/images, changing visibility, editing the description)

How to publish a Mod

1. Navigate to “C:\Users\YourUsername\AppData\Roaming\SpaceEngineers\Mods”
2. Create a new folder, and place your mod inside.
3. Start the game and edit or create a new world, but do not start it – go to the mods options instead
4. Click on your mod
5. You can click the “Publish” button (the button is grayed out for non-local mods)

Troubleshooting

In case you get error message that your image is too large:

1. Exit Space Engineers (this is important since the game won’t register any changes you make on the blueprint files).
2. Open C:\Users\<YOURUSERNAME>\AppData\Roaming\SpaceEngineers\Blueprints\local and find the blueprint you want to publish.
3. Create a new folder in Blueprints\local and place your blueprint files in it
4. Open the “thumb.png” with any image editor (Paint, Photoshop etc.) and resize it to be with resolution lower than 1280×960 and a file size just under 1MB.
5. Overwrite the existing “thumb.png” (I also save it as a “thumb.jpg” to be sure that the workshop page will have an image).
6. Open Space Engineers again, load your world and publish the blueprint.