This update requires that Visual Studio 2013 has already been installed. SQL Server Data Tools can be updated on Professional, Premium, Ultimate, Express for Windows Desktop, and Express for Web SKUs.
For more information, please see the team blog.
To create an administrative install, save the SSDTSetup.exe file locally and run the administrative layout command on a computer with internet access to create a copy that you can burn or place on a share:

• Run the following command using an administrator command prompt (cmd.exe run as administrator):

SSDTSetup.exe /layout <destination>
Where <destination> is the location you wish to create the administrative install point (e.g on a USB drive, a LAN drive or other accessible location).

• To use the install point once created on a computer without internet access, simply run SSDTSetup.exe from the location with no arguments. This will use the install point rather than attempting to download new copies of the relevant chained components.