How to engage 4WD and locking hubs on Isuzu/Holden Rodeo

Brief explanation about how to use that pesky little additional gear box on your truck; the differences between high and low range (and when to use them). Additionally, how and when to use your locking hubs.
The explanations here are provided just to give you enough context to understand why you use the different gears. This is by no means a complete explanation for 4WDing. This is a working vehicle and yes, it needs a bath.
Keywords: 4WD, four wheel driving, high range, high ratio, low range, low ratio, Aisin locking hubs, gearing, truck gears