Hi Ha Nguyen Danh, this endpoint is only for creating a tree structure of folders only.

You will have to then subsequently populate the folders with the files you want, using the usual Add File API. I believe this folder structure API endpoint was added because of the Workflow Action "Add Folder" where you can add a shallow folder structure as part of the action.

It's a shame that we can't upload a ZIP file containing a "repository" of folders and files, leveraging the same process that the front-end makes possible through the "Add zipped files" option.