Coverting from PostNuke/Pagesetter

We have a few websites using PostNuke/Pagesetter, in fact the only reason we are using PostNuke is because of Pagesetter (http://www.elfisk.dk/). It allows me to create simple databases that can store structured content so that I can find, filter, and sort. How can I get MODx to work in a similar fashion? Is there anyone familiar with both systems that can explain it too me? Just point me in the right direction.