How to link multiple implementation files in C

I have a number of .c files, i.e. the implementation files say

• main.c
• A.c
• B.c

Where functions from any of the files can call any function from a different files. My question being, do I need a .h i.e. header file for each of A and B's implementation where each header file has the definition of ALL the functions in A or B.

Also, main.c will have both A.h and B.h #included in it?

If someone can finally make it clear, also, how do I later compile and run the multiple files in the terminal.

Thanks.