How to format a cmake file correctly?

Question

CMake

I want to use the libssh library , but when building the project, the linker sees only undefined functions.
CMake is configured correctly (I hope), in any case, it finds the library, but the functions are still a problem.
CMakeLists.txt:

cmake_minimum_required(VERSION 3.18.4)
project(c)

set(CMAKE_CXX_STANDART 17)
file(GLOB
        CPPS "*.cpp")

find_package(LIBSSH)
if(NOT LIBSSH_FOUND)
        message(SEND_ERROR "Libssh was not found")
        return()
else()
        message("FIND")
        include_directories(${LIBSSH_INCLUDE_DIR})
endif()
add_executable(${PROJECT_NAME} ${CPPS})
target_link_libraries(c ${libssh_LIBRARY})

main.cpp:

#include<libssh/libssh.h>
int main()
{
    ssh_session my_ssh_session = ssh_new();
    if (my_ssh_session == NULL){
        return 1;
    }
    ssh_free(my_ssh_session);
    return 0;
}

The library is installed and located in /usr/include/libssh / .
OS: Linux.