Create multiple buttons with different functions

Hi, I very new to processing and I have to do a project for my university.
I can’t figure out how to build multiple buttons that each have a different function. The whole thing should be a quiz when it is ready. Total of 6 pages, start page with a how to, play and imprint button and the rest for the questions.
Any help on how to set up the buttons would be great!

you need to detect when a button from the mouse is pressed, if it was clicked on certain x and y position, then you execute one function or another. remember to constraint the position, example:

  if(mouseX >= 10 && mouseX <= 90)

the code above will execute the FunctionA() only if the mouse was clicked between the x positions of 10 and 90, you can extrapolate this to constraint the coordinates of the y axis

Thank you very much for your fast answer! I will try this in a minute.