Fa, La, La, Lastic Christmas 12 XL Shaped Card KitCompleted by Jane Williams

That was fun! As they say, it's XL - I'sd suggest an 8" by 8" envelope.

The layers of decoupage are described as "optional", but in reality if you're printing on Craftsuprint paper/card, you need those layers to make it stiff enough to support its own weight. What is optional, thanks to the design, is the extent to which you want to fussy-cut. I've left the base layer with quite a broad margin, then got more detailed on the next level up. That gives the detail on the trees without leaving delicate and fragile tips vulnerable to knocks.

A sheet of backer/iner is provided, but it's straight A4, not shaped to fit the back of the card at all. I've used it here to sit the card on. Maybe it could be used to line a fancy envelope?

The support at the back may well need stronger card to strengthen it. Mine tends to slide open if standing on a smooth surface, but then it's quite thin card, and scored perhaps too well.

Lots of possible sentiments are supplied, as well as options for the back of the base.