Where is all of the Arduino Documentation?
I'd like to add to what JRobert said of finding the information the &quot;hard way&quot;(i.e. looking into the datasheet of the chip it used, and understand how it works from schematic).
In the Arduino world, a lot of hardware/shields are so called Open Source Hardware, meaning that many companies can produce the same hardware with the schematic that is released under Open Source hardware license. China happened to be the country where it has the complete value-chain from components, to manufacturing and cheap labour. They are good in producing such products at large quantity and selling at low price, and they are not necessary good in developing original product, and certainly not in documentation (especially in English). These products are not necessary China &quot;knock-off&quot; as many people call it.
Since it is open hardware products, there are multiple vendors producing it and there are many information available on the internet, and take the example you provide, it is &quot;1602 LCD Keypad Shield&quot;, and if your google it with this phase, you will soon find this pdf which is not exactly from the same company of your shield, but it is remarkably similar that you can try.
This applied to many hardware/shields that are available in the market. I hope this provide a general guidance and an &quot;easy way&quot; to find the information in your tinkering journey. Of course, if you want to learn more, go dig out the datasheet and schematic as JRobert mentioned.