Start by reading Installing mu-plugins section in our comprehensive WordPress MU Manual if you are new to WordPress MU.

To install:

1. Download the plugin file

2. Unzip the file into a folder on your hard drive

Upload lock.post.php to wp-content/mu-plugins/

3. Upload locked.php to wp-admin

To use:

  1. Log in as site admin user.
  2. Go to the post you want to lock and click on 'Edit' ( Posts > Edit )
  3. Scroll down to Post Status area and select Locked
  4. Click Update Post