Note that this process is easiest if you are using Firefox with the extension installed and pop-up blocker disabled.
Run your search in PubMed. Check off the boxes located to the left of the references you would like to save to your EndNote Basic account, and click on the drop-down button next to Send to.
Select Citation Manger and click Create File.
If your computer's settings are optimal, your references will export directly into your EndNote Basic account.
If your references do NOT export directly, the reference file should be saved (probably to your Downloads folder). You will need to manually import this reference file into your EndNote Basic account.
In your EndNote Basic account, click on the Collect tab, then click on Import References.
Click on Choose File and select the file you just saved from PubMed (probably in your Downloads folder). For your Import Option, choose PubMed (NLM). If it does not appear in the drop-down list, click on Select Favorites and add it to your favorites.
You may choose to route your references into an existing group, create a new group, or add them to your [Unfiled] folder.
Click on the Import button. Your references should be imported into the specified group.