For openSUSE Tumbleweed run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mendres82/openSUSE_Tumbleweed/home:mendres82.repo
zypper refresh
zypper install sound-theme-yaru
For openSUSE Slowroll run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mendres82/openSUSE_Slowroll/home:mendres82.repo
zypper refresh
zypper install sound-theme-yaru
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/home:mendres82/16.0/home:mendres82.repo
zypper refresh
zypper install sound-theme-yaru