It looks like you have misunderstood, or not understood how source code files are combined and compiled into an executable file. The sort() and search() functions - two independent and self-contained functions that you write - are supposed to be placed inside of helpers.c while main() exists already in find.c. You should open find.c and review the contents.
The Makefile contains the various instructions on how to build and compile the executable file. Most important is the followiing line in
find: find.c helpers.c helpers.h
It tells the compiler to use all 3 of these *.c and *.h files in combination to build the executable file
BTW, you don't make helpers, you
Perhaps you would benefit from a review of all the class material and videos on 'make', functions structure, and program compiling.
If this answers your question, please click the check mark and accept. Let's keep up on forum maintenance. ;-)