I wish it would start to feel like fall here in Florida -- 90 degree days are definitely not fall like! I love making fall cards and this design is one I really like for any small stamp that will fit through the peek-a-boo window made with punches.
Start by layering your mat onto the front of your card (in this case my mat is the 4" by 5 & 1/4" piece of Soft Suede Card Stock.) But don't attach it permanently yet -- just line it up with the vanilla card front so that a small border of the vanilla is showing just the way you want when it's finished. You can use a temporary adhesive such as Dotto to hold this if you'd like. Then punch through both layers -- the mat and the caard while they're held together -- with the 1 & 3/8 inch Square Punch from Stampin' Up. Now take off the Soft Suede layer and stamp on it. You could of course stamp before punching but I like to know where the window will be as I place my leaves. I used Versamark ink and stamps from the Falling Leaves set, plus some splatter courtesy of tried and true set Itty Bitty Backgrounds.
For the little border that shows through the punch window, I punched a window in a scrap of Crushed Curry card stock with the 1 & 1/4" Square Punch. Attach this in between the Soft Suede mat and the Vanilla card, adjusting it so that a border shows evenly from the outside and when you open the card. It's a nice little detail touch that adds to the look of the card.
I use the window in these as a way to tie a bow or in this case linen thread around the card front and through the window. You have lots of options for this stage. You can tie it around just the mat layer; the mat layer after the Curry window accent's been attached (that's what I did here but I also really like it not wrapped around the Curry layer so you have more color showing); or around the whole card and mat once they're attached.
The Gratitude greeting is from the same set and was stamped in Soft Suede on Dusty Durango and then punched out with the Modern Label punch. I stamp right through the window to stamp the little Happy Thanksgiving circle greeting. The stamp blocks happen to be 1 & 1/4" for many of the small stamps so if your stamp is centered on the block then it's very easy to just line up the block with the window and stamp right through the window on the inside of the card. When adding an additional greeting like the one here, be sure it's low enough that it does not show through the window when the card is closed.
Happy fall y'all!