In order to work with MarkWiki, you need to learn some Markdown. You can either jump right into editing and learn as you go (because Markdown is super easy), or head over to the MarkWiki/Features page to learn more details.
Okay, so maybe you don't actually have an interest in using MarkWiki (that's too bad!), but you need to set it up. In that case, look at the MarkWiki/Deployment page.
We can talk about more questions, of course! The frequently asked ones, in fact. Check them out at MarkWiki/FAQ.
Also, if the main page of your wiki has been changed, find the original at MarkWiki/Introduction.