To move a document from one folder to another, right click on the document you want to move and select Move.
In the modal that pops up, select the new folder you want to move your file to. The selection will be indicated by a check mark next to the folder name. To move your document to the root directory, don't select any folder.
You can also create a new folder in this modal, by clicking on Create New Folder at the bottom of the dialog.
You'll be prompted to name your new folder. Give it a name and click OK.
Your new folder will be added to the list of folders you can choose from to move your file to. You'll have to select it as the folder you want to move to after creating it.
You can't move folders at this time. Only individual documents.