All measurements on this one are metric and you can blow each one up to get a closer look by right clicking over the picture.
You will need four sheets of A4 cardstock, or if you use A3 and juggle the pieces about a bit you should get away with one of those and one A4. Also, a scoreboard, ruler, glue....I uses Art Institute dries clear as it's an almost instant fix and as the name implies dries clear.....two 12x12 sheets of DP and a tassel or large brad for the draw handle. I like to use double sided or coordinating DP as this gives the best visual result. Plus your easel card to fit on top.
Cut out all pieces and score as per the pictures (see note below fig 4 before you cut).
Join A & B on box parts one and two (fig 1&2) by folding over each other butting to the folds, so you have one long piece. Now fold the whole piece round to form a box shape and glue the longest flap over the shorter one - this should butt to the corner fold and give a perfect box shape.