Raspberry pi cmake build problem

guys when i want to build mavsdk with cmake in my raspberry it gives that error
pi@raspberrypi:~/MAVSDK/examples/fly_mission $ cmake -Bbuild -H.
– The C compiler identification is GNU 8.3.0
– The CXX compiler identification is GNU 8.3.0
– Detecting C compiler ABI info
– Detecting C compiler ABI info - done
– Check for working C compiler: /usr/bin/cc - skipped
– Detecting C compile features
– Detecting C compile features - done
– Detecting CXX compiler ABI info
– Detecting CXX compiler ABI info - done
– Check for working CXX compiler: /usr/bin/c++ - skipped
– Detecting CXX compile features
– Detecting CXX compile features - done
CMake Error at CMakeLists.txt:12 (find_package):
By not providing “Findmavsdk.cmake” in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by “mavsdk”, but
CMake did not find one.

Could not find a package configuration file provided by “mavsdk” with any
of the following names:

mavsdkConfig.cmake
mavsdk-config.cmake

Add the installation prefix of “mavsdk” to CMAKE_PREFIX_PATH or set
“mavsdk_DIR” to a directory containing one of the above files. If “mavsdk”
provides a separate development package or SDK, be sure it has been
installed.

– Configuring incomplete, errors occurred!
See also “/home/pi/MAVSDK/examples/fly_mission/build/CMakeFiles/CMakeOutput.log”.

how can i fix it