Welcome to Android Central! It shouldn't be any different between the first few times and the 100th time. Just charge it up until it's at 100% (which should take about 1-2 hours at the most with a 2A charger), then unplug it and use it. If you want, you can continue charging for an additional 1-2 hours after it has reached 100% to complete the saturation charge (which is the phase of charging where the current eventually drops to zero, while the voltage remains steady). See here for more information:
Charging Lithium-Ion Batteries – Battery University
