You can establish a default location for configuration files that contain settings that apply to all conversion projects for a particular DITA document; for example, settings that name the document itself, or that reference values that occur only in that document. You can use a different location for each source document, and you can change the location for each project. Choose a default that applies to most of your projects, depending on which of several possible scenarios is most likely:
Single output type per document
Multiple output types per document
Multiple documents per output type
Configurations shared on a network
Regardless of which default you choose, you will be able to specify a different choice for each project, when you configure default settings; see §2.3 Configuring default DITA2Go project settings.
Single output type per document
If you expect to produce only one output type from each DITA document, and no one else will be working on the same document, you really do not need a document-specific configuration file at all; your project configuration file can include all the needed settings.the best place is Local; configuration files specific to a given document will be stored in a directory adjacent to the output directory for each project.
Multiple output types per document
If you expect to produce more than one output type from each DITA document, the best place is Local; configuration files specific to a given document will be stored in a directory adjacent to the output directory for each project.
Multiple documents per output type
If you expect to produce the same output type from multiple source documents, you might want to keep source-specific configuration files for all documents in the same directory tree, for easy comparison; this would be a reason to choose Central, and use the Browse dialog to specify a parent directory for document-specific subdirectories. The default parent directory is %OMSYSHOME%\d2g\document. You select or create a subdirectory for each source document, at the time you create a conversion project for that document.
Configurations shared on a network
If %OMSYSHOME% is located on a network drive, and more than one person will need to access document-specific settings for the same document, you might want to choose Central.
If you are the only person working on your projects, Central is probably easier: you have all the document-specific configuration files in one area, and if you want to see how you did something in another project, you can easily find the configuration file for that project.
If you need to be able to move entire projects from one machine to another, or if you might have to pack up a project and send it to someone else, choose Local; configuration files specific to a given document will be stored in a subdirectory adjacent to the output directory for each project.