Trivial on Linux.
1. Make sure you have codeblocks-dev package installed
2. Download the files and extract them.
3. Open "SemanticHighlight.cbp" in Code::Blocks
4. Click compile (you will probably get an error in prep.h -- if so, goto project -> build options -> check the "-ansi" flag, which is 3rd item down)
5. Goto Plugins -> Manage Plugins -> Install New... find the just created SemanticHighlight.cbplugin
Now watch as your source is rendered. The thread you linked to and a very superficial look at the code suggests that it can't be configured through the GUI yet.
If you are on windows, I suspect you won't have much luck as there are a bunch of hardcoded linux paths in the sources and you will need to change the project files quite a bit. This is one reason why the plugin isn't in C::B's repo.