Manually Attach Files
Files in your library can be accessed by double-clicking the file in the center column. Alternatively, you can right-click the file and selecting “View PDF” or “View in External Viewer” (for PDFs) or “View File”.
To locate a copied or linked file, right-click the file in the Zotero pane and select “Show File”. Copied files are stored in the Zotero Data Directory, and each file has its own subdirectory, which is named with a random 8-character string.
Importing from Other Citation Management Software
You might want to migrate to Zotero but already have an extensive library stored in other reference management software. To import such libraries into Zotero:
Zotero can import several popular bibliographic file formats including:
If this fails to migrate your data, there are some other alternative options listed on the Zotero support pages.