Systemd is a powerful boot system and it needs some time to learn it. This page lists some tips which might be helpful to new users.
Old timers are accustomed to change run levels with "init 1" (maintenance mode), "init 3" (normal with network but without a graphical user interface), "init 5" (graphical user interface and network).
If used from the kernel command line in grub, these three init commands work as expected, but from a shell command line the behavior is a bit different. If you boot with "init 1" and issue an "init 3" systemd boots the default config, that is network and graphics (expected result for "init 5").
One of the great user friendliness of openSUSE is to have a list of the service available from root by typing "rc<TAB>". All the rc* files, which are links to the /etc/init.d/rc* files, are shown.
The /etc/init.d files are no longer used with systemd, but they now link to the systemd equivalent, so you don't have to change your usual work;
Nonetheless, it is better to learn the new, simple syntax, See systemctl below.
systemctl is the basis of the use and setup of systemd. Typing alone
will give you a report of the systemd use in the computer. Also the list of the services.
systemctl start|stop|status... <servicename>.service
will start, stop, give the status... of the quoted service (root needed to start/stop).