Thank you for choosing Thames & Kosmos and for your interest in our CodeGamer kit.
The error you are receiving (Encoder.h: No such file or directory) is a result of the Arduino software being unable to locate the reusable functions found in the KosmoBits software library. They have to be in a very specific spot in order for the software to be able to find them so that you can use them in your coding so, even if you remember having taken these steps, try them again just to make sure they're in the correct place.
First, download the KosmoBits libraries. This can be done by entering http://thamesandkosmos.com/codegamer/kosmobits_archive.zip into your web browser on your computer. It will automatically download a file called kosmobits_archive.zip
Unzip the file and move to the Arduino libraries folder. Here are the instructions on how to do so.
Then, open the Arduino application to get started. You shouldn't see that same error message this time around.
If you need them in the future, these instructions can be found on page 8 of your manual.
If you have any additional questions about CodeGamer or any of our other products, we kindly ask you to send an email to firstname.lastname@example.org so that a member of our team can reach out to you.
Thank you again for choosing Thames & Kosmos. We hope you and your family will continue to enjoy our products for many years to come.
The Thames & Kosmos Technical Support Team