The direct link to the "Software Platform Bundle" is available at:
http://www.ni.com/download/web-based-installer-software-platform-bundle-spring-2018/7498/en/
This installer has the option to "download" or "install" that hooovahh mentioned.
As far as what is included in this bundle, I don't see a document yet for 2018 Spring, but here is the 2017 Fall:
http://www.ni.com/white-paper/54231/en/