Im trying to start an animation of sprite when timer starts with set_autoplay.
Its good, but it only runs once.
I'm not working with sprites. (I'm doing 3D with godot)
But normally you would start an animation with the play() method of the AnimationPlayer instance.
The autoplay attribute only lets the animation start once when the scene is loaded (or the animationplayer object is instantiated).
Or did you mean the autoplay-animation of the timer? Make sure that the One Shot attribute isn't set.