In order to install Gura-SDDM, you can follow these steps.
$ git clone https://github.com/FireStreaker2/Gura-SDDM.git
$ sudo mv Gura-SDDM /usr/share/sddm/themes/
To actually use Gura-SDDM, make sure to edit your SDDM configuration so that it has the following line:
Current=gura-sddm
If you don't know where your SDDM configuration file is located, you can run
man sddm.conf
for more help.
In order to edit how the login screen looks, you can modify the theme.conf
file.