You'll need the following dependencies:

• meson >= 0.43.0
• libgdk-pixbuf2.0-dev
• libgranite-dev >= 6.0.0
• libhandy-1-dev >= 0.83.0
• valac

Run meson to configure the build environment and then ninja to build and run automated tests

meson build --prefix=/usr
cd build
ninja

To install, use ninja install, then execute with io.elementary.screenshot

sudo ninja install
io.elementary.screenshot