How can I turn LED lights?

Other Hardware LEDs and Multiplexing
4

Sure, use the Debounce to read when the button is pressed.
Each time it is pressed change modes:

if (button_pressed){
mode = 1-mode; // so mode will go 0-1-0-1-0-1...
then switch between modes
switch(mode){
case 0:
//do stuff
break;
case 1:
// do  stuff
break;
}

if you want you can read the button while within each mode also to switch to the other mode