im honestly dumbfounded im a noob modder and need help quick:p
You should be able to open Horizon from your desktop just like Windows 8.
Just click on the desktop shortcut option during the setup.
I did notice a addition folder for horizon installation, so if you had this problem during the installing of horizon, uninstall it, then reinstall it, when it ask where you want to install it put in the drive i.e. C:\Program Files (x86) or C:\Program Files, and make sure that you press create desktop shortcut. doing both step ensure that you will be able to open fine.