Start with the topic guide.
Compiling and linking, data types and sizes, operators, control flow, functions, arrays, pointers, pointer arithmetic, strings, structs and unions, dynamic memory with malloc and free, headers and the preprocessor, file input and output, undefined behaviour, and makefiles.
This is a learning outline. A complete worked tutorial has not been published for this topic yet.
Concept scope
C Language Fundamentals: 15 short lessons, one for each concept. Compiling and linking, data types and sizes, operators, control flow, functions, arrays, pointers, pointer arithmetic, strings, structs and unions, dynamic memory with malloc and free, headers and the preprocessor, file input and output, undefined behaviour, and makefiles.