Linking One by One:
Select the Item / Family Type within each list and then click on the "<->" button to create the link (note how the word "twin" (highlighted) has been used as a search filter to search within the left panel):
Step 1: Verify that the right attribute configuration and correct Family categories are selected. Read more: Introduction to Revit Attribute Configurations and Revit Family Categories
Step 2: Select Item in dRofus. In this example we have used the search field to find the right Item in dRofus
Step 3: Select Family Type
Step 4: Select <->
Step 5: The linked Item and Type will appear in the list over Linked Items.
The Item and Type are now linked an populated with the information set in the configuration.
Select “Sync” to synchronize the instance and occurrence.