No, you don’t understand. I teach high school English. I mean I really know. (Now, don’t go judging my writing–this is a one-woman shop, and I have no budget for editors.)
Here’s a quick guide on how to use an apostrophe in your last name: First, most likely, you won’t do it. Here’s the thing–normally, an apostrophe shows possession. Take this sentence, for example:
Julie’s Diet Coke spilled on her keyboard.
So, what does Julie possess? That Diet Coke. This is the correct way to use an apostrophe.
Too often, you see families throw an apostrophe at the end of their name to show that there is more than one person in the family. Like this:
Smith’s went on vacation to Door County.
Smith’s is just supposed to mean that more than one Smith went to Door County?
Instead, the writer should have written this:
The Smiths went on vacation to Door County.
Of course, if you’re like me and you have a last name that ends with an “s,” there’s a whole ‘nother set of rules you’ve got to wade through. I’ll let you get the scoop and some verification from my favorite grammarian: Grammar Girl.