Both files should have the same name except that the header file has a .h extension while the implementation has a .cpp file. The header file contains the class interface, and the .cpp file contains ...

C/CPP files should include their own header files first and you should enable those warnings you said. But that is not enough: the compiler doesn’t check the names of the parameters, ...

I always have one .cpp file (for function definitions) and one .h file ... (especially a template) in a lot of places, it might be wise to put it in a separate header file and include that.