Get Sources

https://www.haiku-os.org/guides/building/get-source-git/

Create folder (for ex. 'sources' on Desktop)
Open Terminal under sources

Download build-tools (if you want to create an ISO):
git clone https://review.haiku-os.org/buildtools
mkdir generated.x86_64; cd generated.x86_64
./configure --cross-tools-source ../buildtools --build-cross-tools x86_64

Download Haiku source:
git clone https://review.haiku-os.org/haiku




Download Haiku source if you intend to submit changes upstream:
git clone "ssh://Coldfirex@git.haiku-os.org/haiku"
scp -p Coldfirex@git.haiku-os.org:hooks/commit-msg "haiku/.git/hooks/"

cd haiku
git remote set-url origin ssh://Coldfirex@git.haiku-os.org/haiku (Update your existing copy of the source to use the commiter access:)