[blucar]

It would appear that you are dealing with a '35 open face cover, in lieu of the full face '36 cover.
It has been awhile since I had to install a spare tire cover, from memory I'll offer the following suggestion.
1. Place the outer ring onto the tire, keeping same up on the tire tread, near the edge.
2. Place the face cover onto the tire.. Hold the face cover with one hand while grabbing the outer ring with the other had.. Carefully work the outer ring over the face cover..
The '36 covers are easier to mount because the face cover locks to the inner portion of the wheel.. This helps to hold it in place while the outer ring is positioned over the face cover..
Lowering the tire pressure, to near flat, can make the job a little easier.. Re-inflate the tire after the cover is installed..