For the distribution of your materials choose locations where a lot of YMPs regularly pass by or spend their time. This could be close to firms and educational institutions where YMPs work or study, or also close to places like bars, malls or gyms where they pass their leisure time.
You probably won't be able to distribute your materials across your whole city. Instead, you should choose well the locations where you might most probably reach your new target group.
What is important is to provide materials that are really useful for the target group, so they use them regularly in their everyday life and each time get reminded of the topic you want to bring to them.