Advantus Panel Wall Clip for Fabric Panels, Standard Size, 40-Sheet Capacity, Box of 50, White (75342)

You slide the bracket down from above and the T-pins enter the fabric cubicle wall at a shallow angle and the bracket hangs from the pins, tight to the wall. They’re very solid and firm. It’s a similar mechanism to one of these paper wall clips: https://www.amazon.com/dp/B001GXDATS