Problem compiling Aseprite on macOS Monterey Mac 12.3.6

Hello, I followed all the instructions in this youtube video: How to build Aseprite on MacOS | Free - YouTube to compile aseprite. I installed xcode, homebrew, cmake, ninja and I downloaded the source code of aseprite as well as skia on the github: aseprite/ at main · aseprite/aseprite · GitHub
but when I start compiling:
cd aseprite
mkdir build
cd build
-G Ninja

ninja aseprite

it gives me this: mkdir: build: File exists
CMake Warning:
Ignoring extra path from command line:


CMake Error: The source directory “/Users/nathanmichelnkombe/aseprite” does not appear to contain CMakeLists.txt.
Specify --help for usage, or press the help button on the CMake GUI.
ninja: error: loading ‘’: No such file or directory

do you have a solution for me please?
Mac OS monterey 12.3.6