Study!
http://en.wikipedia.org/wiki/Optics
http://en.wikipedia.org/wiki/Charge-coupled_device

http://en.wikipedia.org/wiki/Analog_circuit

http://en.wikipedia.org/wiki/Analog-to-digital_con...

http://en.wikipedia.org/wiki/Diffraction_grating

This one if you want to know how an artisan learned to use the rainbow prism/grating 'physical fourier transform' effect (sorting of light by wavelength) to correct for chromatic aberration in lenses during the early 1800s:
http://www.amazon.com/Spectrum-Belief-Fraunhofer-T...

Solder the circuit board components (work in progress).

Be careful when soldering the ICs (Integrated Circuits), and especially the ADC and most importantly the CCD. Follow the datasheet specifications for soldering, the temperature and how long they can be held at temperature.

Assemble concave aberration-corrected flat-field grating with a slit and the open-Spectrometer CCD.

Connect the USB cable to the open-Spectrometer and a computer.

Ensure the FTDI virtual COM port driver is installed. Ensure Python is installed. Download or clone the open-spectrometer github repository. Copy the contents of the directory desktop-software into your Python installation's site-packages directory (you could copy this directory and rename it to something without a dash, as they aren't allowed in Python module names), or add it to any existing Python script's path manually with sys.path.append(DesktopSoftwarePathString).

See openSpectrometer.py's main() function for an example of how to use the software. (This documentation and the software will be updated as the hardware progresses in functionality)