An alert dialog box is a pop-up window that appears on your screen to give you important information or to ask you a question. It's like a little message that says, "Hey, pay attention to me!" or "Do you want to do this thing?"
Think of it like a parent asking you if you want ice cream. They might say, "Hey kiddo, do you want some ice cream?" and you can choose to say yes or no. The alert dialog box works the same way. It can give you options or just let you know something important.
But, like a parent, the alert dialog box might get annoying if it shows up too much or for things that aren't important. So, while it can be helpful, it's important to use it at the right times.