"Where did all this shit “start” is there like a guy who “declared liberalism” or something, or does it evolve with time? What’s the root of all this shit?
This unfortunately isn't something that can be explained succinctly. Marx developed dialectical materialism for explaining the processes of how these things develop over time. That's what you'll really want to look into. Knowing general world history is an important place to start though, since you'd need context on a lot of stuff.
To answer one question, Adam Smith was one of the first to look at how the economic order was changing in the late 1700s and develop a theory to describe what was emerging. If by "inventing" capitalism you mean he came up with the idea of individuals owning private property and operating it to produce commodities and generate profit, then no. He saw people were already starting to do that just based on the changing levels of technology, interconnected trade, and population growth and wrote extensively about it and its implications. Often, he thought many of the developments were actually bad (or had bad repercussions that needed amending at least), and was critical of this emerging capitalist system. Marx was a fan of Adam Smith and used a lot of Smith's writing as influence in some of his works.
This unfortunately isn't something that can be explained succinctly. Marx developed dialectical materialism for explaining the processes of how these things develop over time. That's what you'll really want to look into. Knowing general world history is an important place to start though, since you'd need context on a lot of stuff.
To answer one question, Adam Smith was one of the first to look at how the economic order was changing in the late 1700s and develop a theory to describe what was emerging. If by "inventing" capitalism you mean he came up with the idea of individuals owning private property and operating it to produce commodities and generate profit, then no. He saw people were already starting to do that just based on the changing levels of technology, interconnected trade, and population growth and wrote extensively about it and its implications. Often, he thought many of the developments were actually bad (or had bad repercussions that needed amending at least), and was critical of this emerging capitalist system. Marx was a fan of Adam Smith and used a lot of Smith's writing as influence in some of his works.