Sroll down in your Creative Cloud panel, and you will see a Find Additional Aps : Previous Versions bar. Click on that to see a list of programs, and click on the install button of InDesign to see a list of versions to choose from.
How can I roll back my update...?
Read this post: Re: New InDesign UI is wayyyy too large (2015.4) including the quote of Peter Spier and the links within, as well as the 2 subsequent posts; Peter's #138 and my #139.
I think what you mean is roll back to 11.3, not 10.x. You can do that too, by uninstalling and reinstalling ID CC 2015, then downloading the 11.3 patch from ProDesign Tools. All Adobe CC 2015 Updates: The Direct Download Links for Windows | ProDesignTools or All Adobe CC 2015 Updates: The Direct Download Links for Mac OS | ProDesignTools