linking shared libraries with cmake on ubuntu - linux

Question

I am trying to link to shared object library (json-c) using cmake. I am a super beginner with cmake, and have tried the solutions in various SO posts to no avail.
I am following the directions laid out here
first step is to build the json-c library, which I did sucesfully.
Second step is linking to it. That's what I am having issues with. After following these instructions, my project directory structure looks like this:
Project Structure (before running make, build directory was empty)
base
|-json-c-master
|-libjson-c.so
|-libjson-c.a
|-json.h
:
:
:
|-CMakeLists.txt
|-Makefile
|-libjson-c.so
|-build
|-CMakeFiles
|-
:
:
|-Makefile.
|-src
|-main.c
|-project1.c
|-project1.h
The contents of my CMakeLists.txt in ~/base/project1/CMakeLists.txt
cmake_minimum_required(VERSION 3.10)
project(project1) set(CMAKE_CXX_STANDARD 14)
set(SOURCES src/main.c src/project1.h src/project1.c )
add_executable(project1 ${SOURCES})
find_package(json-c CONFIG)
target_link_libraries(${PROJECT_NAME} PRIVATE json-c::json-c)
then, I ran
cd build
cmake -DCMAKE_PREFIX_PATH=/home/<username>/base/project1/json-c-master ..
this populated the previously empty build directory.
then, I ran make
and I got the error that in project1.h, which #includes "json.h", the file "json.h" was not found.
How can I link json.h to project1.h?
I again appreciate your patience, I am a super noob with cmake and I've been pouring over their documentation and other SO posts to no avail.