Thanks for adding tutorials to the site. It has been a while since i coded so it is a great help for users like me.
However, the tutorial about the Nokia 5110 display refers to a source file which is not there:
Download the NavSpark Example Code Files from our Resources page and open the GPS Graphic LCD demo (demo_gps_info_graphic_lcd_Nokia5110)
On the resources page i can only find the Arduino-NavSpark-Example.zip file. And this file does not contain the demo_gps_info_graphic_lcd_Nokia5110 file.