There should be a quick word about system requirements, followed by a link to Manual:Installation requirements. I would suggest inserting it as item 1.4 or 1.6. It doesn't need to say much more than:
Q: What are the system requirements for installing MediaWiki?
A: Simply put, you will need a web server, with PHP, and SQL. Commonly this means Apache, PHP5, and MySQL. More detailed information can be found at Manual:Installation requirements.