To set include paths for your program:
Choose the menu item Settings->Compiler and Linker Settings … and click on the Include Paths tab in the Compiler Options dialog.
Enter each of the paths one by one and click on the Add button for each entry.
To remove an entry, select the entry in the list and click on Remove.
To edit an entry, select the entry, modify it in the text box and click on Update
To clear all of the entries, click on Clear.
|Things to note|
If the settings are for a project, then all include paths should be relative to the source directory of the project. Avoid using absolute paths — otherwise, when you distribute the source code, other people will have problems trying to build the program.
If the settings are are made outside of a project, then it doesn't matter whether the paths are absolute or relative — the settings will be local to your machine only.