Multifile Projects via shell script?

Question

Qt Creator

Build a multi-file project using a shell script. The project consists of three files main, file1 file2. In main, the functions from file1 and file2 are called.
I would like to know where you can find information, some literature, to solve this task. I have no idea where to start, what program should I work with, where should I write the code? How to merge these files, using maybe an IDE editor (OS-creator) or a plain text one will be enough? But if text then how to merge into a multi-file project?