So setting up the design is the hardest part of this, first I like to measure what I am putting inside of this to get the measurements, I added 10mm to each side to allow for airflow and ease of placing inside. One way I like to do this is with the alignment tool making the little cuts in the squares you can place a small rectangle (in this case material is 3mm and I want it 10mm long) inside of the side piece and align to left, top, then combine subtract at overlap. and repeat for the others. Note: just remember that you will have to do all this for any difference is size of what you are holding up. Once you have all your sides and everything done you can cut this out I used Xtools plywood and cut it out. 

Now that all the parts are cut out and you are ready to move on start with the smaller parts and glue things up lots of clamps are needed or you can do one at a time. I use two on the sides to hold it all together. Now depending on the glue you are using will determine how long you have to wait to remove the clamps. Once it is all dry you have completed the assembly! 

Attaching the holders. on the underside of your desk or shelf where you are placing these I used double sided tape to secure them Note: if you are not in a climate controlled environment you might need something stronger. Once they are secured where you need them placing the wire is easy if it is flat you will need to put in sideways then twist. If it is round wire you can slip it right in and allow gravity to do the rest!

The power block is a bit heavier and will require a bit more tape. once you have this mounted up you can plug it all in and you are done!