You can use Library Search or a subject database to discover a reference to a book or article and then export that reference to EndNote. It can save time, as you do not have to enter all the information about that reference into EndNote manually.
Databases from a supplier usually all work with EndNote in the same way. So you just need to read the instructions for the supplier eg EBSCOhost and they should work with whichever database from that supplier you're using.
We've written instructions for our main subject database suppliers.