Hi @TeacherHelen, nice to meet you! The Papercraft Spectrometer wiki is a good place to start. There you will find links to instructions for calibrating the spectrometer as well as activities to get you started. Some of the demos are shown with the desktop kit, but if you're using the foldable on your phone, you will just default to the phone's camera. Once you've calibrated you can move on to some of the other activities to start getting a feel for what kinds of things you can do. As you use the spectrometer you can also upload your data to the gallery Spectral Workbench, where you can look at other people's work and share your own (including any questions about what you've captured). Hope this helps!

Dear @TeacherHelen, you can use the following free software created for android platforms, you can get information about it, from the calibration and additionally the construction of a miniaturized spectrometer in a 3D printer

https://publiclab.org/notes/omarormachea/10-20-2017/smartphone-spectrometer

Regards