SDDM depends on PAM for authorization and XCB to communicate with the X server. Also it depends on Qt for user interface and event loop management, apart from other things. SDDM can optionally make use of systemd login manager or upower to enable support for suspend, hibernate etc.

SDDM uses CMake to configure the build and it can be compiled with the typical cmake build process:

mkdir build
cd build
cmake .. -DCMAKE_INSTALL_PREFIX=/usr
make

After successfully building the software, type following to install.

sudo make install

When found, systemd will be used for power management. When systemd is not available, sddm will fallback to using upower. If upower can not be found either, shutdown/reboot/suspend/hibernate actions won't be available. Note that, when systemd is found, the HaltCommand and RebootCommand configuration options have no effect.

After installation, sddm can be configured by placing files in /etc/sddm.conf.d/. Consult the sddm.conf man page or the output of sddm --example-config for documentation about available options.