In reviewing through your description there are a few options which should be available to move content.
If you are wanting to do this on a per document/content basis, the following steps should work:
1. Select Edit
2. Change the the location to "The Main Community" option and select publish:
After doing this you should see the location change present at the top of the document and its visibility set to everyone. For example:
Additionally, if you are interested in performing this type of task in bulk here are a few add-ons that might be of interested to you:
Along with an idea posted here, Bulk Content Operations, suggesting this as a feature enhancement to the platform.