Here’s the latest instalment from The WordPress MU Manual
Now that you have set up your MySQL database and username you are ready to install WMPU following the steps outlined below:
Downloading WordPress MU
1. Download the latest zip version on WPMU from mu.wordpress.org
2. Unzip the downloaded file to a folder on your hard drive.
Downloading and Using FileZilla To Install WordPress MU
The easiest method of getting files onto your site, and once there, changing them is using a FTP (File transfer protocol) client. FTP works by transferring files from your computer to your site.
FileZilla is free FTP software that works well on all Windows computers. Its screen is split into two halves; left half shows the files on your hard drive and the right half shows those on your web server.
For Mac Users try using Cyberduck; free FTP software designed for Macs.
You use FileZilla as follows to install WPMU:
1. Download and install FileZilla
2. Launch FileZilla
3. Enter your domain name, your username and password. NOTE: the same username and password that you use to log into your cPanel.
4. Click Quickconnect
5. Locate and open up your WordPress MU folder on your hard drive.
6. Double click on your public_html folder to open up the root directory of your site.
7. Hold the SHIFT key, and press the DOWN arrow on the keyboard to highlight all the files and folders in the WordPress MU folder on your computer and drag it into your public_html folder on your site.
8. Dragging the code from the WordPress MU folder on your computer into the root directory of your site uploads the WPMU code to your site.
However it doesn’t complete your WPMU installation. Check this by viewing your site in a web browser – you should now see instructions for installing WordPress ц.
Now… to complete installation you need to:
a) Change permissions on the public_html and wp-content directories
b) Delete the .htaccess file
Which are coming up next :)