Because of the popularity of our illustrated guide to balloon mapping, which also ships in our retail kits, I spent some time making the attached 2-page PDF showing how to construct a spectrometer. It doesn't cover how to use it, and focuses on specifically how the current spectrometer kit is made (i.e. a particular webcam), but aside from being useful to ship in the kits, I imagine we can continue to expand and revise it as we did the original balloon mapping guide.
Here is the PDF (1.4 MB): PLOTS DIY Spectrometer Guide v1.0.pdf
(If you'd like to edit, modify, or translate it into other languages, here is a link to the Google Doc where I made it -- for translations, please clone it and post your translation as a comment on this post!)