How To change O-RING for SALTED LINE flat port with 67mm thread for Sony E 55–210mm lens

HOW TO CHANGE O-RING FOR SALTED LINE Flat port with 67mm thread for Sony E 55–210mm lens
https://www.saltedline.com/collections/flat-ports/products/flat-port-with-67mm-thread-for-sony-e-55-210mm-lens-40m-130-ft