Folders allow you to quickly file your references under different topic headings. You can drag and drop references from your library into the folder in the left panel to add that reference to a folder. You can also create folders within existing folders.
In Mendeley, click the “+Folder” icon to create a folder that will appear in “My Library” on the far left side bar.
Once you’ve added PDFs to your library, you’ll also be able to open them for reading within Mendeley. This offers you a number of opportunities: