You could take the Splunk Fundamentals 1 class. It is a free, online, self-paced class that gives you the fundamentals of getting data in, searching, reporting, alerting, dashboarding. If you do it start to finish it should take you about half to 3/4 of a day from what I have heard.
As for searching that data, you may also want to start with any existing apps / add-ons available on splunkbase.com for free. For example, there is an add-on for CWS, and an app, Cisco Security Suite, which provides visualizations for that and many other Cisco security related sources of data. You can always utilize what is in those dashboards, and even look at the searches behind the panels to learn how they were created.