If you're using any TurnKey derived system, you don't need to install it as TKLBAM is a bundled into the TurnKey Core.
If you're using a generic Debian or Ubuntu derived system you can install it with the following shell command:
wget -O - -q \ https://raw.github.com/turnkeylinux/tklbam/master/contrib/ez-apt-install.sh \ | PACKAGE=tklbam /bin/bash
This adds the TurnKey package repository to your APT sources and uses APT to install the tklbam package and its dependencies.
Using TKLBAM on TurnKey Linux provides the best experience but it will also work well with any Debian or Ubuntu derived system and even with other Linux distributions if you install from source and use the --skip-packages option to disable integration with APT, the Debian package manager.
When you use TKLBAM with TurnKey Linux it takes advantage of the known fixed installation state to make the smallest possible backup. For example, it will only backup /etc configuration files that you have changed. This makes migration easier by increasing visibility into what actually changed. By comparison on a generic Debian or Ubuntu system it will backup all /etc configuration files.