Segmentation w/ Scissors Tool

Operating system: macOS Catalina 10.15.6
Slicer version: 4.10.2
Expected behavior: Use scissors tool to segment abdominal aorta model into multiple pieces for later printing
Actual behavior: Nothing happens when I use scissors to determine new segment. Im not sure if I am using the wrong settings but can’t seem to segment the model into portions that can then be individually exported as .STL’s

I guess you need to provide bit more details perhaps with screenshot to see what happens and your workflow

Thank you for the quick response. Unfortunately, I will now be out of the lab until Monday. I will be able to screenshot then. Is there anything, in particular, you would need to see?