1. Download the plugin file
2. Unzip the file into a folder on your hard drive
3. Upload multi-domain.php to the /wp-content/mu-plugins folder on your site
There is no folder called "mu-plugins" in wp-content. Do I create it?
4. Upload sunrise.php to the /wp-content folder on your site – If you are using the domain mapping plugin, rename dm_sunrise.php to sunrise.php and upload it to the /wp-content folder on your site
5. Edit wp-config.php (normally located in the root of your install) and the following: define( ‘SUNRISE’, ‘on’ ); (Please ensure that you type this and not just copy and paste – Take care with the back-ticks)
That leaves us with a folder that is not included in these instructions. The folder is called multi-domains-files. Where does that go? The instructions do not mention it at all.
Also, editing this post takes me to the edit screen where almost all of the css is broken or missing.