Part Two of the tutorial series on building real-time maps with geolocation tracking using the Google Maps API and PubNub focuses on adding and updating map markers on an Android application. The tutorial explains how to configure the necessary settings from Part One and implement the MainActivity file to initialize PubNub for real-time communications and display a live-updating map marker. The LocationSubscribeTabContentFragment is responsible for handling Google Map initialization and subscribing to PubNub message events for location updates, employing a scheduleRandomUpdates() method to simulate location changes. The tutorial also details how the LocationSubscribePnCallback and LocationSubscribeMapAdapter classes are used to manage asynchronous PubNub events and update the UI on the main thread. By the end of this part, the application can plot map markers and update their positions based on real-time data, setting the stage for further enhancements in Part Three, which will cover detecting and plotting the device's location in real time.