To import libraries from EndNote, you need to export the libraries from EndNote first.

Edit -> Output Styles -> Open Style Manager  and select BibTeX Export style.

 Then follow File -> Export -> choose Text File and click Save button

After exporting from EndNote, click on the gear icon above the left pane in your Zotero and select “Import” from the drop-down menu. In the file system window that pops up, locate the BibTeX file you exported from EndNote.

Click Open button. This should import your references into Zotero in the Imported Sunday….folder in the left pane and items appear in the middle pane of your Zotero.