Confirm the downloaded repository is configured by checking the repo list:
zypper repos
You should see the Ambari and HDP utilities in the list:
# | Alias | Name 1 | AMBARI.dev-1.x | Ambari 1.x 2 | HDP-UTILS-1.1.0.15 | Hortonworks Data Platform Utils Version - HDP-UTILS-1.1.0.15
Install the Ambari bits using zypper. This also installs PostgreSQL:
zypper install ambari-server