Connector Identification; How to Case Mount
This is a variation on a style of panel mount commonly used for switches. It snaps into a rectangular hole.




Note the flange on the left end. One dimension of the hole should be just large enough to fit the connector body and then stop against the flange. (Prettier versions of this style have a flange that goes around all four sides.)
The other dimension of the hole should be wide enough that the wings can be squeezed to fit past it. The ridges on the wings will then press against the hole edges and prevent the connector from coming out of the hole, and can do this for a variety of panel thicknesses. (Make sure that your rectangular hole has a crisp edge on the inside for best grip.)


I recommend making sure you are prepared to cut a rectangular hole with neat, straight, intentionally dimensioned edges. Use a file and test fitting to get it to final size so that you don't accidentally remove too much.