Windows Security Operations Center: After installation, I see four systems identified on the "About" tab, but why don't I see any info in the login events tab or any others?

I'm new to Splunk. I just installed the WSOC app and I see four systems identified on the "About" tab, but I don't see any info in the login events tab nor any of the others? What am I missing? I am using universal forwarders on these systems.