如何更新WPF应用程序中的appSettings ?

Greetings to all! This is my first question here on stackoverflow. I have a WPF application that I am writing for the fellow developers in my department, and there are a couple of settings that I need to check for at startup and update if they are not set (one is the location of an executable on the users computer, we all have it, just not in the same place). So when my app starts up for the first time, I need to pop a filechooser to have them select the location.Greetings to all! This is my first question her