How to Transfer Vivado HDF Hardware Def File and Vivado SDK Code

How to
Transfer Vivado HDF Hardware Def File
and
Vivado SDK Code
to a new SDK project.
You only need the .hdf file, and your .c code.
Assuming: you already have a finished, compiled Vivado project, with a bitstream file generated. And your Vivado SDK code consists of just the helloworld.c that you wrote.
Using Vivado 2018.
Using CModA7 board with Xilinx Artix7 FPGA.