Follow this article to update a multi-Select List attributes, using the Customer Data Hub.
Multi-Select List allows you to choose, in the UI, more than one value from a pre-defined set of values. This can be also achieved in the Customer Data Hub, using any source. The following example will use the CSV.
Data Source Format
Before setting up the source data, make sure the values aligned with the pre-defined in Totango.
The selected values should be divided with a comma, surrounded with double quotes:
in Excel it will look as follow: