Very delicate and risky operation

Remove the broken window of your mini S4 is a delicate operation which requires heating the glass with a hair dryer or a heat gun instead. The problem is that it must be heated sufficiently to soften the glue, but not too much to prevent damage to electronics. So, ideally, you need a laser Thermometer to control the heating.
In short, I recommend you watch the tutorials on YouTube carefully before you embark on the adventure!