The scabbard has a couple of places for some snaps. These snaps have a rather wide base that can be put behind some fabric, with the shaft going through a hole in fabric. The snaps can then be inserted into the scabbard.
I know I'm not being too clear. That being said, one of the snaps failed on me and I replaced it with a zip type cable tie. This works pretty good.
The vest I have has an general purpose attachment point which can be seen in this photo.
I used it and a trademark label that is below the attachment on mine to attach the scabbard to.
It also has a clip, but I don't trust it. Especially the way I have it oriented (upside down)
The wife had to use her's last year on the Middle Fork (for something other than making a sandwich). Had to cut loose a oar that had broke as we were going through Powerhouse.