To start you will need to cut the following pieces, all pieces will be 8 and 1/4" wide.

One 6"

two 4"

three 2"

You will then need to score all the pieces across the 8 and 1/4" width at

2" 4" 6" 8"

this should leave you with a 1/4" tab on all pieces. If you mitre the tab then add a little adhesive and stick each piece around to create various square tubes.

For the three 2" pieces we need to poison them horizontally, if you fold the pieces you have already stuck down flat so that the two 4" pieces are both two panels wide and lying a panel wide of the 6" piece, the widest piece at the bottom. Take the 2" pieces horizontally and adhere one side only to the bottom left panel then the bottom right panel and then the panel adjacent to the bottom right, when you pop it out it should look like this.