How to use makefile?

Question

GNU Make

I came across such a utility as make file in Bruce Eckel's book, but I did not understand anything. How to use it? Need to create another file and write commands there?
- Good.
What extension should the file be? .h/.cpp?
What does this line mean:
g++ work pointer.cpp Source1.cpp Source2.cpp
work pointer, Source1, Source2 file names in the program.
Where should I enter this line? In the main file? in the make file? Someone explain clearly what it is and where.

Answer 1

Basics here
https://habr.com/ru/post/155201/