There should have been an icon created on your desktop by default. As long as you did not change the install path it should be C:\Program Files (x86)\OBS\
If it is installed and you cannot locate the install path try right clicking on your desktop icon and clicking either 'open file location' or on properties, and that will display the install path.
If you cannot locate the program anywhere, you may just be best to reinstall it as there may have been an issue with the install and it may not have installed everything.
