./build_ros.sh error

Hi , i'm trying to install ORB-SLAM3 on Ubuntu 20.04 but i'm facing some error first i export path >>> export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:/home/ai/catkin_ws5/src/ORB_SLAM3/Examples/ROS but still have same error and i have 5 workspace

./build_ros.sh Building ROS nodes mkdir: cannot create directory ‘build’: File exists CMake Warning (dev) in CMakeLists.txt: No project() command is present. The top-level CMakeLists.txt file must contain a literal, direct call to the project() command. Add a line of code such as

project(ProjectName)

near the top of the file, but after cmake_minimum_required().

CMake is pretending there is a "project(Project)" command on the first line. This warning is for project developers. Use -Wno-dev to suppress it.

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:7 (cmake_policy): The OLD behavior for policy CMP0011 will be removed from a future version of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all policies are deprecated and that a policy should be set to OLD only under specific short-term circumstances. Projects should be ported to the NEW behavior and not rely on setting a policy to OLD. Call Stack (most recent call first): CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:16 (cmake_policy): The OLD behavior for policy CMP0002 will be removed from a future version of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all policies are deprecated and that a policy should be set to OLD only under specific short-term circumstances. Projects should be ported to the NEW behavior and not rely on setting a policy to OLD. Call Stack (most recent call first): CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:18 (cmake_policy): The OLD behavior for policy CMP0003 will be removed from a future version of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all policies are deprecated and that a policy should be set to OLD only under specific short-term circumstances. Projects should be ported to the NEW behavior and not rely on setting a policy to OLD. Call Stack (most recent call first): CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:20 (cmake_policy): The OLD behavior for policy CMP0005 will be removed from a future version of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all policies are deprecated and that a policy should be set to OLD only under specific short-term circumstances. Projects should be ported to the NEW behavior and not rely on setting a policy to OLD. Call Stack (most recent call first): CMakeLists.txt:2 (include)

CMake Deprecation Warning at /opt/ros/noetic/share/ros/core/rosbuild/rosbuild.cmake:23 (cmake_policy): The OLD behavior for policy CMP0011 will be removed from a future version of CMake.

The cmake-policies(7) manual explains that the OLD behaviors of all policies are deprecated and that a policy should be set to OLD only under specific short-term circumstances. Projects should be ported to the NEW behavior and not rely on setting a policy to OLD. Call Stack (most recent call first): CMakeLists.txt:2 (include)

[rosbuild] Building package ORB_SLAM3 [rosbuild] Error from syntax check of ORB_SLAM3/manifest.xml Traceback (most recent call last): File "", line 1, in File "/opt/ros/noetic/lib/python3/dist-packages/roslib/init.py", line 50, in from roslib.launcher import load_manifest # noqa: F401 File "/opt/ros/noetic/lib/python3/dist-packages/roslib/launcher.py", line 42, in import rospkg ModuleNotFoundError: No module named 'rospkg' CMake Error at /opt/ros/noetic/share/ros/core/rosbuild/private.cmake:77 (message): [rosbuild] Syntax check of ORB_SLAM3/manifest.xml failed; aborting Call Stack (most recent call first): /opt/ros/noetic/share/ros/core/rosbuild/public.cmake:174 (_rosbuild_check_manifest) CMakeLists.txt:4 (rosbuild_init)

-- Configuring incomplete, errors occurred! See also "/home/ai/catkin_ws5/src/ORB_SLAM3/Examples/ROS/ORB_SLAM3/build/CMakeFiles/CMakeOutput.log". make: *** No targets specified and no makefile found. Stop.