To develop applications, you first need to create a project that will contain your source code and related files. The project will have an associated builder that incrementally compiles source files as they change.
The IDE provides the New Project wizard to create new projects. If you're writing an application from scratch, you'll probably want to create a QNX C Project or QNX C++ Project, which rely on the QNX recursive Makefile hierarchy to support multiple targets. For more information about this recursive hierarchy, see the Conventions for Recursive Makefiles and Directories chapter in the QNX Neutrino Programmer's Guide.