To fetch entries from ACM, choose Search -> Web search, and the search interface will appear in the side pane. Select ACM portal in the dropdown menu. You may choose which database to search and you may opt to download the abstracts along with the cite information for each entry, by checking the Include abstracts checkbox. To start a search, enter the words of your query, and press Enter or the Fetch button.
Frequent connections to ACM Portal may get your IP banned for hours. To avoid this, JabRef will for each search display a preview of the first page of entries returned by the server. You can then choose which entries to download.
Then, the results are displayed in the import inspection window.