I am trying to trigger a signal with parameters but I am struggling to figure this out. Basically, I have 2 scenes (menu and play) and I have a scene controller scene as well.

Here is an example of my tree:

SceneController:
     Menu:
     Play:

Scene controller has it's own script, and menu has it's own script (referenced below). There is a "play" button on the menu scene.

On my menu scene:

extends Control

signal change_scene(scene_name)

var scene_name: String = ""

func _on_btn_play_pressed():
		scene_name = "play"
		emit_signal("change_scene", scene_name)

and on my scene controller:

extends Node

@onready var current_scene = $MenuScene

func _ready():
	current_scene.change_scene.connect(self.handle_level_change)

func _process(delta):
	pass

func handle_level_change(target_scene_name: String):
	var next_scene
	
	match target_scene_name:
		"menu":
			next_scene = load("res://scenes/MenuScene.tscn").instance()
		"play":
			next_scene = load("res://scenes/GameScene.tscn").instance()
		_:
			return
			
	add_child(next_scene)
	current_scene.queue_free()
	current_scene = next_scene

My goal is, when the play button is pressed, then the scene will change to the play scene. I want this to be managed from the scene controller and load the scenes as child nodes.

During debug, everything on the menu is happening properly, and the signal_emit is happening with the assigned variable. However, the scene controller is never seeing the signal.

Any help would be greatly appreciated.

    robertsw easy - you aren't telling the game when to do the function.

    See, you can write functions all day but you have to have the editor "listening" for them, or they won't work. You just need to put your _on_btn_play_pressed() in the _process(delta) line.
    You also need to tell your program what input to expect. I built a separate function for it here but you can probably wrap it up in one. So you need to add:

    func _listenForPlayPressed():
        if Input.is_action_just_pressed("ui_confirm"): ### put whatever button you're using in the editor here
            _on_btn_play_pressed


func _process(_delta): ### put an underscore here before delta if you want to avoid warnings
       _listenForPlayPressed()

    That is WAY over-abstracting it, but should work.