The "reference " folder must be an existing folder, where the data dictionary will be used during the intialization of the folder. A link is made between a folder and the reference folder. Thus, by default, if a resource (process, table, report) is not found in the current folder, it is looked for in the reference folder, by an inheritance mechanism.
This value is taken by default in the copy folder, the folder from which, during the creation of the folder, it is possible to copy certain data (parameters, accounting plan...) as well as indicated in the Init tab.