I went down to the hardware store, and found there were two sizes of tub lever covers, so I bought both sizes, intending to return the other unneeded one.
The lever cover screws were easy to remove, and fortunately, the brass linked rods and plug were easy to fish out.
It turned out that the part of the lever just behind the cover had cracked and broken.
I lined up the old linked rods on a flat surface, adjusted the new rods to the same length, gave the new plug a thin coat of silicone grease, and it went back in easily, with a little flexing to persuade the rods to go around the opening lip.
I screwed in the new cover, tested the plug and it holds back water great!
I returned the unneeded plug mechanism to the store for a refund.
Great job on returning the unused one! I used to forget to return the unneeded item until it was too late. I have gotten better at it.
I know, that’s why I had to return it the same day. Otherwise, it’s going to take up residence in my junk drawer.