Part Two of the beginner series on building real-time maps with geolocation tracking delves into adding map markers using the JavaScript Google Maps API, the Geolocation API, and PubNub. This tutorial demonstrates how to visually represent device or user location on web and mobile maps by initially placing a single map marker and updating its position randomly. The code walkthrough explains setting up an HTML5 application with the PubNub library for real-time communication and Bootstrap CSS for styling. Instructions include defining initial latitude and longitude, using trigonometry to determine marker movement, and implementing event handlers to update map positions dynamically. The tutorial highlights connecting the map to PubNub for real-time data streaming and subscribing to a channel for position updates, concluding with initializing Google Maps API to ensure all prerequisites are met. The next part will focus on using the watchPosition method to detect and plot real-time device locations.