Tween animation - opacity


I want to add tween animation opacity to an object, but when i select the object I want, it says “The behavior is not attached to this object. Please select another object or add the behavior”
Can anybody tell me how to add the behavior?
I want to create like a fade effect

P.S I’m a newbie to gdevelop so please go in details :smiley:

Any help would be appreciated, Thanks :smiley:

In the editor, edit your object there is the Sprite tab for animations and besides the behavior tab, just add there the desired behavior