If you want to make a segment, but not sure how to filter out just the contacts you need, you can add a new value just for this purpose. 

This can be useful, for example, if you want to filter just the contacts starting with a particular letter. 

Adding a new column

If you have your list outside Mailigen platform, just add a new column and create a new easily distinguishable value, for example, “1” and import these details using “update existing subscriber details” option. Follow the steps in video.

• Filter your contacts outside the Mailigen platform and add a new value, for example, "1" in a new column.
• Name the column as you would like to see it in your list in Mailigen platform.
• Copy the new updated list in your excel document.
• Go to your list and choose "add subscriber" → "paste from excel"
• Paste your updated list. If you have copied the names of the columns, tick the checkbox "first row in the file contains column headings"
• Tick the checkbox "Update existing subscriber details" and click "update subscribers" to continue.
• Find the new column, name it and click "add new field"

Creating a segment based on the new value

After you have added the new value, creating a segment should be easy. 

Follow the steps in video

• Create a new segment, based on the list and name it.
• Under "subscriber based filter" choose the newly created column,
• Choose the appropriate condition 
• Enter the value that the segment will be based on.
• Click "create"