In order to create this box (and finally get everything to fit right)  I used https://www.makercase.com  to create the box.  The software is free to use.  You can set the parameters for either the inside or outside of your box.  You are limited on downloads per month but these files are easy to use.

Once I had the pattern I used the snipping tool and brought the file into XCS.

Hold down the shift key and select each piece.  Or two if you think you can get them on one workspace.  

Group them.

Place on a new workspace

Then trace the design and separate.

Release the compound vector.

Highlight the inner most line and delete it. (if you don't it possible your pieces won't fit right. )

I purchased a file from an etsy shop. https://etsyshop.com/shop/KimichArt titled Geometric Laser Cut Patterns.   I used pattern #Asset 42 for this project.

Bring the asset in as a png.

Place it inside the piece you will be cutting.  

Size it (you will need to release the maintain aspect ratio in the upper left of the screen or your design will not fit from top to bottom or left to right.

Trace the file and separate.

Once you have it placed where you want it, and at the appropriate size release the compound vector.

Select and delete the outer line.  (If you don't the design will fall out of the box)

Set all your parameters to cut. 

Stain or paint according to your design idea.  Let them dry.

I put these together in two steps.

Match two pieces and put glue in the lower teeth of the finger joint on them.

Secure them with corner clamps to dry.  This will ensure that you do have a 90 degree angle when the box dries.

Do this for the other two pieces.

Then connect the pieces, add the bottom and again use the clamps until dry.

Add the top.

Congratulations!  You have completed this project.