Given the wiki article you mention above, the suricata binary should have been installed at /usr/local/bin/suricata which means the template suricata.service file will need some editing.
The wiki article is pretty much complete, but we have no coverage of hooking into systemd yet.
For a more complete experience, and assuming you don’t need any custom compile time options, you could try the RPMs that we prepare. These work right out of the box with systemd.
See: Guide: Suricata RPMs for CentOS and Fedora
The RPM is still at 6.0.0, however the 6.0.1 is in the -testing repo and will be moved to the primary repo in a day or so.