EndNote: Importing Citations from
ACM Digital Library

Create the EndNote library in which you want to store the citations. Or, you may use an existing one.
Search the ACM Digital Library as you normally would.
From the result list, click on the title of the article you want to keep. This will bring up the "full citation."
Under Tools and Actions, look at Display Formats. Click on EndNote.
Click on OPEN.
Choose the EndNote library in which you want to store the citations.
Click on OPEN.

Check your references to make sure they were imported correctly.
Once they are in your library (your database) you can edit them as desired.