This is one of those "if you have to ask, you shouldn't be doing it" questions. In the store I used to own, I'd have new techs work on destroyed phones, practicing screen replacement until they could do it without damaging the phone even further. And these were techs who knew how to open a phone and replace components.
We see many posts here from people who replaced their own screens, then come here asking how to fix what they obviously broke.
You'll save a little money doing it yourself - and then spend 5 times what you saved to get the phone working again. Save money and pay a shop to do it.