First setup WordPress, then follow these steps to configure it.
Many multisite plugins still need to be installed in this folder.
Windows LiveWriter is the best WordPress editor, and it uses XML-RPC
Admin > Settings > Writing
Admin > Settings > Permalinks
Even if you think you won't need more than one WordPress site, do it anyway just in case.
Add to wp-config.php
Shows Tools | Network in WordPress admin to enable multisite
Paste what you are told to wp-config.php and .htaccess
Remove from wp-config
Admin > Super admin > Options > Upload settings > Media upload buttons
Check "Images" to support "Featured images" in themes that support it
Used by all sites on the entire network
Used by individual sites
Categories and tags
Tags are global, but not categories
Use the Sitewide tags extension to add global tags on the portal front page or on specific pages or sites within the network to increase navigation based on micro-categorized content.
WordPress can power multiple top-level domains, not just subdomains.
Customize WordPress with extensions.