Right click anywhere in the left hand pane to create folders and sub-folders. You can drag and drop files into folders from anywhere.
You can select a document and add tags in the right hand details pane and then search for tag names to find a group of documents easily.
Tags work much the same as folders, with the key differences being that it’s easier to add lots of tags to a document than it is to drag it into several folder.
Search for a keyword in the top right to find documents instantly as you type. The search includes global notes and tags by default and you can filter specifically by clicking the filter arrow.