If you don't have VR controller or your VR headset doesn't provide any controller functionality, than this is the best application for you! You can download the mobile app from the play store and the windows center app from http://www.lebersoftware.hu/vrmousecontroller
With this app, you can connect to your phone from your PC/Laptop and with a windows application you can use your wireless mouse to touch the screen in VR games to control them.
!!!You have to install driver to let your PC recognise your phone this way. You can find the driver for Samsung phones in the zip package if you download the windows center app from here. If you don't have samsung phone, you should install google USB driver on your PC. If you get "Error, cant connect to phone. USB driver installed?" message during verification, then your driver IS NOT PROPERLY INSTALLED. You can install google USB driver this way as well: https://developer.android.com/studio/run/win-usb.html