You'll need the following dependencies:
gobject-introspection
libglib2.0-dev
libgranite-dev >= 6.0.0
libnotify-dev
libwingpanel-dev
meson >= 0.58.0
libjson-glib-dev
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