First time with fondant cut-outs- can I decorate them with royal icing or should I use buttercream? How soon can I decorate cut-outs before event- weeks/ days?

How should I attach fondant cut-outs to buttercream iced cake?

Thanks for your help- new to this site and cake decorating!!!

The cutouts can be decorated with royal, and they can be decorated well in advance, even weeks. Keep them separated and in a covered container to prevent dust and light.

You can attach them to your cake with buttercream or royal. if you are attaching them to fondant, a touch of water works just fine.

even melted fondant works well.