In the response body you’ll see the information about your home directory and all content within that directory. In the above example the ID of the chosen folder which is "Folder 1" is b5774c2a-82c2-4853-ada7-efcad4fdf325
You can use any id with a "type": "D" which stands for a directory. Note that the "parent_id" is the ID of your Quatrix account.
Once you get the ID you can upload your file(s) to the chosen directory (Folder 1). Check more details here.