Please open Creative cloud Application
Sign out and sign back in Sign in and sign out to activate Creative Cloud apps
Make sure in Creative Cloud Application,Latest Versions is Expanded and Find Additional Apps is set to show "All Apps".
Or Simply you can Click on this link https://creative.adobe.com/products/download/lightroom?promoid=KSPGB
Sign in with your Adobe ID
Click Launch Application
Does it start installing Lightroom CC 2015?
Hope that helps