In Switch a job can be an individual file or a job folder.
An individual file is treated as expected.
A job folder represents a set of files that moves along the flow as a single entity, for example a page layout with its accompanying images and fonts, or the individual pages in a book. A job folder may contain nested subfolders (which can contain other files and folders, recursively).
To submit a job folder to a flow, simply click the Submit Folder button - just like you would click the Submit File with a regular file. The job folder will be submitted to and moved along the flow as a single entity.
PowerSwitch can disassemble jobs into separate files if so required, but not every flow uses this capability. Thus it is important to know, for each submit point, whether its flow supports job folders or not.
See also working with folders.
Sometimes a particular job spawns another related job. For example, a preflight application might generate a preflight report about the job. This report is a separate job (most likely a single file) since the original file is still there as well. Most often the report is named for the original job (with a different suffix), but in the current version of Switch there is no other way to show the relationship between the two jobs.