Verify you have everything in the bag, there should be an assembled and tested PCB, a 2-pin and 3-pin 3.5mm terminal block. The backpack does not come with header or an LCD.
The terminal blocks allow you to easily attach and remove the LCD from your wiring, which we think is awfully handy. If you dont want the terminal blocks (they stick out a bit) you can always skip this step.
The terminal blocks come in 2 and 3-pin pieces . Slide them together.
Next we will attach the backpack to the LCD. First we must put header onto the LCD, if you bought the LCD from us, it will come with a stick of header. Otherwise, pick up some standard 0.1" male header
These photos shows a 10K potentiometer, you can ignore it
If the header is too long, just cut/snap it short so that it is 16 pins
Next you'll need to solder the header to the LCD.You must do this, it is not OK to just try to 'press fit' the LCD!
Now we will attach the backpack. We will show how to do this in a permanent fashion. If you think you would like to remove and replace the LCD at some time, you can use a piece of 16-pin long 0.1" female header as a socket but be aware it will stick out a lot.
There are two options, you can tuck the backpack behind the LCD
The extra two pins are for the backlight. Your LCD doesn't have a backlight. Here's a picture of the backpack board layout, with pins 15 and 16 located. Just leave those empty. Cut the pin header down to 14 pins instead of 16, and attach your LCD to holes 1-14 in the backpack.
If your LCD has 18 pins, you won't be able to use the extra backlight pins, just connect 1-16 and leave 17 and 18 disconnected