MediaWiki’s Help page, at least on the Mozilla Wiki, is far too complex. One of the first topics it covers is the occasional need to do a dummy edit to refresh the internal database caches. I suggest this is unlikely to be uppermost in the mind of most people visiting that page. How to do a link is on the 5th page down on my large monitor, and how to emphasize text is on the 8th page.
Here’s Help:Me, a much simpler page which attempts to show the most important things by example. Do let me know what you think.