To install, copy the plugin file for your operating system and DFHack version to hack/plugins folder inside your DF folder. Then start DF and type remote-update in the DFHack console to install the remaining components. You will need to restart DF if installing for the first time.
Note: On 64-bit Linux systems, 32-bit openssl package is required, e.g. sudo apt-get install openssl:i386.
Refer to http://mifki.com/df/setup for manual installation instructions.