git submodule add -b morty https://git.yoctoproject.org/git/poky ./sources/poky-morty
git submodule add -b morty https://github.com/meta-qt5/meta-qt5 ./sources/meta-qt5
git submodule add -b morty https://github.com/openembedded/meta-openembedded ./sources/meta-openembedded
git submodule add -b morty https://git.yoctoproject.org/git/meta-ti ./sources/meta-ti
And add your own meta layer. eg.
git submodule add https://github.com/jumpnow/meta-bbb ./source/meta-bbb