The first step is just gathering the people together to survive.
The next step would be to find people who know how to do things (like large scale agriculture, smelting, etc.).
The next step after that would be to disseminate that knowledge across your fledgling kingdom.
If someone wants to make the case that it would be fun for the society to start out just "knowing" out to do that, that's fine. But seeing people casually argue that people would just "know" how to make swords makes me wonder how much thought they've put into it.
There's a great book called "The Year 1000" which talks about everyday life in that year. I think it is very safe to say that any medieval historian would find it amusing to be told that the average peasant had the knowledge to make, for example, a weapons-grade bow.
In the game, Fallen Enchantress, the world is about 150 years out from a castastrophe that wiped out 99% of the population and laid waste to the landscape. There are plenty of swords, bows, and other equipment out there. The challenge is regaining the knowledge to make these things in a short amount of time.
A typical game of FE lasts about 40 "years" during which time an extraordinary individual has founded a settlement from nothing and attracted a few thousand people from the wastes. During that relatively brief time, they'll regain virtually all the knowledge they lost including the knowledge on manufacturing high grade steel weapons, armor, siege weapons, construction, etc.
The people aren't primitive. They already know what they need to learn. They have examples of what they want to make. That's why they're able to uncover it so quickly. But yea, they do have to uncover it still.
Moreover, anyone who argues that people would "know" how to do this stuff should really think about that for a minute. They wouldn't know. But they can find out. And they do in the relative blink of an eye.
There's a great book called "The Stand" which I imagine quite a few people here have read. They go through the same thing. There are two groups and they get into a race in trying to figure out how to use stuff that we take for granted in our modern lives.