I suspect that people are overestimating in their replies how much could be done with Wikipedia. People in general underestimate a) how much technology requires bootstrapping (metallurgy is a great example of this) b) how much many technologies, even primitive ones, require large populations so that specialization, locational advantages and comparative advantage can kick in (People even in not very technologically advanced cultures have had tech levels regress when they settle large islands or when their locations get cut off from the mainland. Tasmania is the classical example of this. The inability to trade with the mainland caused large drops in tech level). So while Wikipedia makes sense, it would also be helpful to have a lot of details on do-it-yourself projects that could use pre-existing remnants of existing technology. There are a lot of websites and books devoted to that topic, so that shouldn't be too hard.

If we are reducing to a small population, we may need also to focus on getting through the first one or two generations with an intact population. That means that a handful of practical books on field surgery, midwifing, and similar basic medical issues may become very necessary.

Also, when you specify "ordinary men and women" do you mean who all speak the same language? And do you mean by "ordinary" roughly developed world countries? That's what many people seem to mean when questions like this are proposed. They could alter things considerably. For example, if it really is a random sample, then inter-language dictionaries will be very important. But, if the sample involves some people from the developing world, they are more likely to have some of the knowledge base for working in a less technologically advanced situation that people in the developed world will lack (even this may only be true to a very limited extent because the tech level of the developing world is in many respects very high compared to the tech level of humans for most of human history. Many countries described as developing world are in better shape than for example much of Europe in the Middle Ages.)