My glass is broken but it still work

I am not sure if you screen is cracked and you can still see the picture and only want to replace the glass or if the LCD or digitizer is broken and you have no picture or touch funtion. Because if you need to remove the whole display as a unit then this sites step by step guides can show you how to get the display out if you go to the teardown section.(iPhone 6 Teardown)

If you are wanting to just replace the glass then you may want to watch a instructional video on youtube. If you type in iphone 6 glass replacement in the search field on youtube it should bring up quit a few videos you can watch. I recommend watching how it's done before trying because it is a lot more challenging and time consuming then replacing the whole display. It is also cheaper to just replace the glass so I see why someone would choose this option.