"If your wish is to become rich in Skyrim, joining the Thieves Guild will be one of the first things that you need to prioritize.
Joining the Thieves Guild can be done as soon as you start the game. They’re located on the underground sewer of Riften, a city that can be found on the southerneast side of the map.
Now, what is the process of joining the Thieves Guild? What are the benefits of it?" - JPS