My guess, is that you have a metal block of stereo with a receptical for a plug that has all the convienient labels, and no plug.
Fortunately, all is not lost, With a little exploration inside the stereo unit, each connector on the back can be identified. As little as two are necessary to make your stereo operate, most likely eight or ten will get your stereo fully functioning.
It's important to write down solutions and processes as you discover them; then later you can refer to them as a guide in the event that you need to retrace your steps as we go along. By freeing our attention from trying to remember everything, we have more energy to discover new things.
In my teenage days, several decades ago, I was handed many car stereos, with no wiring harnesses and I succeeded in wiring them up, 99% of the time; . . Mabe 98%.
The process is fairly basic, If you're willing to use a screw driver on your stereo; I'd be willing to show you what to do.
If you're more the, "buy a new piece to plug into that socket, then I'd reccomend posting a "Wanted . . " item in Craigslist, I always say, "If they made one, they made a hundred of them, so there's bound to be one around someone willing to part with."
I'll send a picture or two to try this system out, I'll use my desk stereo as a model, it's a Sony CDX-S2210, with no connector, I retrived from the recycling bin , On the inside, all brands have to do essencially the same thing (when it comes to the connectors on the back),
If we can share some clear pictures, this will be 100 times simpler.
Not too bad, 150Kb files is the most we can get right now, this will work well.
More to come, I have to sleep.