Help........... I'm so confused

Alpine, Jovibarba (rollers), Jovibarba heuffelii, Sempervivum,Echeveria and etc. How can I learn to tell the difference by just looking at them? What is the real difference anyway? When I bought Black Prince (Echeveria) all I saw when I looked at it was a beautiful shaped and color Hen & Chick. You see! They are all the same to me. I sure would like to be able to talk with you all on the forms, but I don't have a clue how to. Yes, I'm embarrassed, but then you all already knew I'm as dumb as dirt on these forms. The one thing that I do know is I love them all no matter what they are, and always will pay postage if you have: those that get in parked cars,lol, those you throw over the fence, those you put on the compost pile, any you have to thin out, or any you just don't want. My home is their home no matter what they are. Now, how do I know if I have a Alpine plant? I have bought so many from so many places that weren't labeled

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Wanted to put "will pay postage" in bold letters but do not know how to do that either!!! duhj.
Going to Lowe's for pea gravel then I'm going outside to play in my anything plants. Hugs everybody. Have a blessed day.