Creative cloud desktop app from http://creative.adobe.com > Download center tab. Once you installed CC desktop app, you will have to install InDesign from within CC desktop app. Along with InDesign, its shared components will be installed.
Adobe download assistant will also be downloaded initially if you download from the trial page of Adobe InDesign CC. You'll then have to login into Adobe Download Assistant with your Adobe ID and password to download the trial version on your PC/Mac.