Please be more specific.
"VS C++" - you mean Visual Studio?
"ctrl+F5" - you want to start debugger without debugging? That is almost always the wrong answer. You want to press F5 to start debugging.
Most likely you haven't opened the solution. Starting VS does not automatically load a solution unless you specify one. Therefore there is nothing to debug. Open the solution that contains the code you want to debug. If you're using VS 2019 then the Start Window should pop up when you first start VS. Inside there is a list of recent solutions and projects you've opened. Select the solution from there. If you are running an older version of VS then you can get to the recent solutions using the File menu. In either case load the solution containing the code you want to debug (it must be in a project) and you will then have the option to debug (F5) to compile and debug the code.
Debug a C++ Program
Learn to Debug C++
Solutions and Projects