I have a GUI Interface with Add, Edit, Delete, Filter, Sort, Search methods.

How do I connect the coding for each of the methods above to the GUI Interface so that when the buttons are pressed, the correct method is called and the required output is seen.

Let's say that I want to add an information or filter something. When I click the appropriate button on the GUI Interface, the correct option has to pop up for me to do what I want to do, in this case, add or filter.