I found the documentation on the bulk loader and the metadata, however, the description regarding the metadata.properties is not specific enough for me.

I have created 3 customer content types each with a set of additional properties. They all extend from the File type.

I dont understand a coupe of things:

• what are the required properties for a basic file type? I see description, source, and subjects in the online doc? Does source specify the file location?
• How do I specify which custom content type a particular file is?
• How do I determine the set of properties available to specific in the metadata.properties?