There are two types of these Graphical LCDs available in the market. One with solder pads both above and below the display and the other with solder pads only on the bottom of the display. The one that we are using belong to type 2, where there are pads only under the display. Both the modules work the same and hence the connections are the same for both. So irrespective of what module it is you can follow the tutorial.
As said earlier Nokia 5110 Graphical LCD has 84 pixels in horizontal and 48 pixels in vertical. The total display size is 1.72’ x 1.72’. The module has 6 input pins using which we can interface it to any microcontroller through SPI communication. The interfacing IC that communicates between the display and the Arduino is the Philips PCD8544 display controller IC whose datasheet can be found here. However if you are using Arduino to communicate with this IC then we need not worry about the datasheet since there are libraries that are ready to be downloaded and used.