@sannin The header file is available as part of the sqlite3-dev package but you'll need to set up the build system to access it. Alternatively, you could download the header from the sqlite3 GitHub repository, but I expect you'll hit some other issues if you take this course. If you are developing C/C++ code for any IoT device with limited resources you really should set up the build system so you can cross compile and thereby have access to a huge range of development resources.