Again this is quite easy, but you must remember some important steps
(1) Firstly, your program must be fully debugged and working before attempting optimisations. Use this test code if you are just testing.
(2) Next go back to Project > "SolutionName" Properties. Now after selecting Configuration Properties, change the configuration from Active(debug) to release. You must change the output directories to the C drive again even though you have done so before (for debug config). Check getting started to refresh your memory.
(3) Now simply select Build > Profile Guided Optimization > Instrument
update, optimize and Run Instrumented/Optimized Application in order.
You should see that your code will run rather quicker than before!