Metallicity
You must create a directory in which you be working on this exercise. It would be helpful to create a new directory for each exercise to keep things in order. The next step is for you to obtain the data file which containes galactic coordinate, metalicity, and color data and place it into your directory.
This data file was obtained from the Sloan Digital Sky Survey using the SQL query. It was then processed to include necessary fields. Further exercises will have you go through these steps for yourself, but for now you may accept the file as it is.
You are now ready to begin working with the data. Launch R from the star menu, or where you have it installed. Click on File -> change dir and navigate to the directory that you set up.