The first step is to set the environment variable COMMON_IMAGE_VERSAL to the full path where you have downloaded the Versal platforms corresponding to your tool release. This edit should be done in the 09-ddc_chain/Makefile file.
VERSAL_VITIS_PLATFORM = xilinx_vck190_base_202320_1
VITIS_PLATFORM_DIR = ${PLATFORM_REPO_PATHS}/${VERSAL_VITIS_PLATFORM}
export VITIS_PLATFORM_XPFM = ${VITIS_PLATFORM_DIR}/${VERSAL_VITIS_PLATFORM}.xpfm
# Set SysRoot, RootFS and Image
export VITIS_SYSROOTS = ${COMMON_IMAGE_VERSAL}/sysroots/cortexa72-cortexa53-xilinx-linux
export SDKTARGETSYSROOT = ${VITIS_SYSROOTS}
export KERNEL_IMAGE = ${COMMON_IMAGE_VERSAL}/Image
export ROOTFS = ${COMMON_IMAGE_VERSAL}/rootfs.ext4
export XLNX_VERSAL = ${COMMON_IMAGE_VERSAL}
export PLATFORM = --platform=${VITIS_PLATFORM_XPFM}
export SYSROOT = ${SDKTARGETSYSROOT}