How to create and connect a Timer in GDScript - Godot 4

Here's how to create a timer along with different options in GDScript:

# creating a timer can be done in any function, not just _ready
func _ready() -> void:
  var timer = Timer.new()
# the timer will last 2.5 seconds
timer.wait_time = 2.5
# if you want to start the timer automatically
timer.autostart = true
# or you can start it manually
timer.start()
# if you want to run the timer only once
timer.one_shot = true
# _on_timer_timeout is the function that will be called when the timer
# finishes
timer.timeout.connect(_on_timer_timeout)

# add the timer to the scene
add_child(timer)

func _on_timer_timeout() -> void:
  print("Timer finished!")