I want to know how to put a second video after the first video ends

    Please explain to me so I understand, I can't.

    Do you know how to use signals in Godot?

    Assuming you have nodes VideoStreamPlayer1 and VideoStreamPlayer2 with the two streams loaded, add this to the script attached to their parent node:

    @onready video1: VideoStreamPlayer = $VideoStreamPlayer1
    @onready video2: VideoStreamPlayer = $VideoStreamPlayer2
    
    func _ready() -> void:
        video1.finished.connect(_on_video1_finished)
    
    func _on_video1_finished() -> void:
        video2.play()

    This assumes that video1.play()is called somewhere in that script.