Here is a link to an article I wrote on this topic for you to read: https://www.gardeningknowhow.com/ornamental/flowers/roses/rose-deadheading.htm
Knock Out and Home Run roses do not need to be deadheaded unless you want to. I deadhead mine as I like to keep them looking tidy. If you do deadhead them, prune off the old spent blooms as close to the base of the old bloom as you can. This is especially true of the Home Run roses as they push out new buds so very close to the base of the old blooms. Cutting things off too far down with sacrifice many future blooms.