Confirm the downloaded repository is configured by checking the repo list.
zypper repos
You should see the Ambari and HDP utilities in the list. The version values vary depending the installation.
# | Alias | Name 1 | AMBARI.dev-1.x | Ambari 1.x 2 | HDP-UTILS-1.1.0.16 | Hortonworks Data Platform Utils
Install the Ambari bits using zypper. This also installs PostgreSQL.
zypper install ambari-server