Instructions
Download the Aloft installation files from its website (at wowinterface.com/downloads/info10864-AloftBeta.html#info). Copy these files to the "Addons" directory in your World of Warcraft installation. You can find the "Addons" directory in the "Interface" directory.
Type "/aloft waterfall" in the in-game message box to open the Aloft configuration.
Choose the menu options on the left of the Aloft window to alter various properties of the enemy tags. For example, you can resize the frame or change the appearance of the name text, among many other options.
Click the "X" in the top-right corner of the Aloft configuration dialog to save your settings and close the window. Now, approach an enemy target to see your customized tags in action.