Thank you for responding!
I have now debounced the switches, but I dont know what to do with the code. I have some experience with C++, but I am still learning to use the Arduino (and this library).
First of all, how do I use the evaluation function to turn on/off the LEDs? And when I added a serial print for when I pressed a button it didn't work? Does it have anything to do with the fact that I had to make it append when the switch state changes? If so, how do I do that?
Thank you so much!