The app is not that complicated after about 15 minutes of clicking around. You can post test content but be aware that help and emergency help request will be broadcast so these two functions should not be tested. Posting a SitRep and expiring in 3 hours will not hurt and you can label it "Test" so others know what you are doing.
To get training the best option is to visit our YouTube channel. It contains videos on specific functions and an overview. The PubSafe app is full of functionality that follows the same flow throughout the app. Once you get a feel for the flow, the rest will come easily.