How to Debug an Infinite Loop

When i lived in spain, that was basically what our coding classes were like. And there are points where i remember arguing with some one in the class being just like, nowi i think that this is how you do it. So ive talked for a long time, i want to bild this, like, really simple web ap for the dog park. You can sign your name, the dog's name when you're coming. Other people can see that, they can sign up for the time, and then after 24 hours, it just forgets everything and you just start again. And i don't want any p i. I just want to do that. Well, what