If you must use CS6, the safest route is to install a licensed version on a dedicated older machine. For modern needs, looking into or the Creative Cloud subscription provides a much more reliable and professional experience. Do you need to open existing InDesign (.indd) files ?
The portable version of InDesign CS6 offers many of the same features as the full version of the software, including:
Here is the reality check. Any "portable" version you download is a cracked, modified executable. While convenient, you must follow the "best practices" for safety: