For uploading a CSV file to UserIQ, you must already have the CSV file created, see here for information on creating a CSV.
Click your name in the upper right corner of the menu bar and click Site Settings.
1. On the menu to the left click CSV File Management
2. Navigate to the Upload New File Tab
3. Provide a name for the file
4. Locate the file to upload
5. Select the file
6. Click Save Column Values at the bottom of the page once the content appears (You can only select one column from a CSV – please be advised that you would have to create multiple CSV files in UserIQ if you would want all of the columns in a multi-column CSV)
Now the file will be available under the Audience and Segment filter User Attribute in Uploaded CSV
Please note that you would have to use a single column CSV (all values in one column) to successfully use it in the segments as audience filters. Displayed below is an example of a list of user_id's in a single column.