In MQX 3.8.1, build MQX libs with #define BSP_ENABLE_CPP 1 in your user_config.h.
Now refer to the example application called "cplus".
c:\Freescale\Freescale MQX 3.8\mqx\examples\cplus\
This one is hello world type of an application using MQX in C++.
Ad 1.
either: create new bare metal project and then add MQX *.h and *.a file (header and libs) of your board (in the \lib\<board_name>.<compiler> folder of your MQX installation directory)
to the compiler, assembler and linker properties of your build target.
or: use CW 10.2 New Project Wizard to create a new MQX 3.8 application, select your board and then example "cplus" project. This will create a new "cplus" application in your workspace, with all compiler, assembler and linker properties already set up for linkage with MQX 3.8.1 libraries.
Ad 2.
If you create a new bare metal application, you shall configure properties of compiler/assembler/linker manually in the properties of your build target.
If you create a new MQX 3.8 application, the new project wizard will configure the paths to the MQX header files and libraries for your <board_name>.<compiler> automatically.
If you're mixing C++ and C source files:
-make sure names of the source file(s) are not shared, for example, hello.cpp and hello.c should not be in one project
-you can call C functions from C++ source file. you just need to tell the C++ compiler that it should link the C function as a C object, using keyword: extern "C"