For Arch package install, first edit the file /etc/pacman.conf, to include the following:

[cingg]
SigLevel = Optional TrustAll
Server = https://cinelerra-gg.org/download/pkgs/arch
# end of cingg

Then run these commands to install it:

    pacman -Sy
    pacman -S cin

To remove Cinelerra-GG run:

    pacman -R cin