sure thing, the only reason i asked about the output of the command
ceedling version is just to verify that ceedling was installed correctly.
so there is a ceedlling command ceedling new < directoryName> that you can run to create the proper file structure to be able to test your source files.
This command creates the project.yml file, src directory and test directory.
if you already have your source files, you can run ceedling new <directoryWithSourceFiles> and ceedling will build around it. There are some assumptions that are made by ceedling though, it expects that the directory where your source files like is labeled src/ if it is named something else, an empty src/ will be created. But this is not needed because all you have to do is look for src in your project.yml file and replace it with the appropriate directory where your source files live.
you need unity because that holds all the asserts that you need to verify your functions. like TEST_ASSERT_EQUAL(), TEST_ASSERT_FALSE, exct.
cMock is used mocking 3rd party or self created files that are called or used in the source file that you are testing.
ad ceedling is a build manager that makes your life super easy.
I hope this helped a little, if not, then I apologize.