Quick Summary: get all instances of a specific family type , get the Owner View, get a parameter from the Owner View, use that parameter to lookup another value in an Excel sheet, then drive an instance parameter back into the family instances based on the Excel lookup.
Get and Set to Instances
Source: What Revit Wants
This has three inputs: an element list, a single parameter name, and a list of values to set to that parameter. The two lists should match in length for predictable results. The values must match the data type allowed by the parameter in Revit. After setting the values, this node returns the now-modified elements as an output.