Newbie: Multifile Projects Getting Started

I have been using the TI Tiva Launchpad and C for many years , but intermittently. Unfortunately with multiyear breaks, I have forgotten almost as much as I knew. I am now looking at an online project that involves a real time clock. The author generously has posted his code in GitHub. I only ever worked on programs with a single C source file. This project has more than one source file and header. It also has files I do not even know what they do. Can one of you kind souls tell me how to set this project up in Kyle including where to put each file ?

github.com/.../Experiment18-RTC

Thank you.