Start with a 12x12 piece of Cardstock and you will need score at 4" and 8", turn it one turn and score at 4" and 8". On each corner from one score line to the other mark and cut away part of that corner piece. I show you exactly how in the video.
Mats are cut at 3 3/4"x3 3/4" you will need a total of 11 pieces. With two of the pieces you will split them from one corner point to the other to make a triangle to glue on to of the inside pockets.
To make the top your cardstock is 8 1/4"x8 1/4" you will score at 1 and 2 inches on all 4 sides. Cut away the 3 outside squares on each corner leaving the one tab to glue the top together.
Glue the tabs together and then fold the end piece over to reinforce the top.
Cut your mats for the sides at 3/4"x3 3/4" and glue on. Glue the top mat on and decorate. I tied mine together with a ribbon, but you can leave it as is.
Thanks so much, E