Installing 32 bit libraries on arch linux
Refresh the package list first after adding repos: pacman -Syy
Regarding pacman-key --init: you can set up pacman for the use with signed packages. By default pacman will accept unsigned packages. So this step is optional and also requires further steps. Refer to the arch wiki for the whole process: https://wiki.archlinux.org/index.php/Pacman_package_signing
You can search for packages named lib32 with: pacman -Ss lib32