1. Preprocessing: The preprocessor obeys commands that begin with #, also known as directives
Commands for the preprocessor are called directives. Directives begin with a pound sign, and they do not end with a semicolon.

Example:
```c
// 
#include <stdio.h>
```
2. Compiling. A compiler translates then translates the program into machine instructions. 
3. Linking: The generated objects are combined to create a complete executable.

The preprocessor is typically integrated with the compiler.