The printer is capable of printing up to 4 colors for a single print.  But keep in mind, the machine will load/unload a filament for each color change within a layer.  This can add significant time to your print.  

To set up a multi color print, again make sure you are in "Prepare", click the object and look for the paint bucket icon from the top menu. The icon is the most right icon in the image here. 

Use the paint or fill tools to set the color. Remember you are printing in 3D. Be sure to rotate the object to inspect it from all sides to see what will print.  Left click and drag with the mouse to rotate.

Click "Slice Object" for a print time estimate. Remember, multi colors will greatly increase print time. Be sure your appointment covers your print time. 

Print going to take too long?  You can either print the object smaller or 'Erase all the painting' to return to single color print.