Mendeley Reference Manager has a three-column structure interface.
1. The left-hand side column (column 1) provides you filtering options such as 'All References', 'Recently Added', 'Recently Read'.
2. The column in the middle (column 2) shows you the references that you imported to Mendeley Library from your research.
3. The column on the right-hand side (column 3) displays the details (or metadata) of a reference that you selected from column 2.
Please note:
4. The 'Add new' button
You can use the 'Add new' button to add references into your Mendeley library. You can add one file or multiple files into Mendeley library by selecting 'Import file(s) from computer'.