How to Make Money and How Trade Route Works in Civ 7?

Hello everyone! A week ago I bought Civ 7 Settler's Edition and while I've been enjoying the game so far especially after the updates, there are two things that still confuse me:

1. How do I make money? I've been consistently making a little to no money, somewhere around a few dozens of gold per turn but I've also seen some people can make hundreds or even thousands of gold per turn. I play on "governor" settings.

2. How does trade route work? Whenever I recruit some merchants, the game suggests me to establish trade routes to certain cities along with some information about resources, but then I get no gold per turn unlike in older Civilization games. Do I need to do anything before that so I'll get some gold in return?