It's very confusing what you're asking - it should be as simple as opening any other application on your computer.
But without vital details it's very hard for anyone to give you clear concise instructions.
If you can take a moment to read this very useful thread, it has great pointers as to the information you should include in your request.
If you are asking about how to launch it..double click InDesign.app/InDesign.exe. Simply go to /Applications->Adobe InDesign CC->InDesign.app (mac) and Start Menu -> Adobe InDesign CC on win.
Welcome to the community and thanks for the post.
If you've installed InDesign CC through the Creative Cloud desktop application by clicking on the install button, then after installation, you'll be notified within the CC desktop app that the product is installed and up to date. However, from within the CC desktop app, there is no option to launch the product directly.
A desktop shortcut is created for the application you just installed for eg: Adobe InDesign CC on your desktop which you can double click to launch the app. The original location of this application is under:
C:/Program Files/Adobe/Adobe InDesign CC(64 bit)/InDesign.exe
/Applications/Adobe InDesign CC/Adobe InDesign CC.app
You can navigate to the above location based on your OS and then launch the application if you're unable to find the desktop shortcut.
Hope that helps.