The Setter is usually all you need. It can be harsh for some decals, just use enough to get the decal to stick down, don't soak the decal with it. You most likely won't need the Softer, but if you do, use it sparingly, let the decal dry a bit between applications. If there are alternate decals in your set, try it on those first on a junk model before you commit to it using it on the decals you want to put on the model. And if you use Future for a clear coat, make sure it is fully cured, at least 24hours.... If you rush the decalling, it can bite you, but if you take your time with these products, it will look gorgeous.