The article below is just a basic introduction to the topic. For something more advanced, written by pros and a fantastic leveling guide, my recommendation would be this Elder Scrolls Online Leveling Guide. I could not find any other guide that comes even close in terms of the impact it had on me.
Hammerfell is another large nation located in Tamriel. In 1E 420, Dwemer was the first to settle the nation of Hammerfell. The nation of Hammerfell is full of harsh dry that made it hard to flourish without proper knowledge. It took settlers of the Redguards to help Hammerfell flourish.