If you are creating an advantage and there is no opposition, rather than rolling you simply gain the aspect with one free invoke. That aspect grants scale as previously described.

If you are creating the advantage on someone else to their detriment, such as casting Entangled by Animated Vines on your foe, you may gain scale on your effort to create the advantage.

If you are creating an advantage via supernatural means and an opposing party can directly impede the effort via physical or supernatural interference, your scale may apply against their defend roll.

Otherwise, you roll to create the advantage without scale (likely against a set difficulty), but later use of that aspect grants scale when appropriate.