You can either create a segment using the Adobe Experience Platform Segmentation Service or you can access and create them directly in Journey Orchestration.
In the top menu, click on the Segments tab. The list of Adobe Experience Platform segments is displayed. You can search for a specific segment in the list.
Click Add to create a new segment. The segment definition screen allows you to configure all the required fields to define your segment. The configuration is the same as in the Segmentation Service. Refer to the Segment Builder user guide.