Low-cost graphic Nokia 3310 LCD shield & Joystick

Hi Guy's/Gals I need some help Pleaze. First I'm still learning so bear with me. My end goal is to have the shield display "functions" like a temp reading say from a LM35 but I'm stuck.

The sample code shows how to compile a menu and use LCD_3310_write_string ,LCD_3310_draw_bmp_pixel etc.

Can some one please explain the charmap sample and LCD_write_byte as per the library. Or maybe guide me to a link were I can learn more.

It would seem that the Nokia_3310_lcd library is more developed, but that just confuse me more as it is written for the color display.

Also the display from this shield is a Nokia 5110 right and not a 3310?

Thanks