You'll need the following dependencies:
libaccountsservice-dev
libgirepository1.0-dev
libglib2.0-dev
libgranite-dev >= 5.3.0
libgtk-3-dev
libhandy-1-dev >= 0.90.0
libwingpanel-dev
meson
valac
Run meson to configure the build environment and then ninja to build
meson build --prefix=/usr
cd build
ninja
To install, use ninja install
sudo ninja install