First of all, you need to fix the touch panel part firmly on the machine plate with 4 adjustable fixed tools. The heating plate is made of integrative alloy-aluminium so it can endure the high temperature.
And then turn on the machine and set the temperature you want. Normally 100 degree is good enough to melt the glue. Note that DO NOT touch the heating plate of the machine, otherwise you may get hurt by the high temperature. You can see the real time temperature from the LED display on the side of the machine. And when the temperature gets to the set degree, it will beep to let you know.
While waiting for the temperature rising, you can prepare some strong alloy wires. You can bind the wires to something handy like sticks or pens, and now wait for the machine beeps.
When it beeps, it means the temperature has reached the set degree. And the glue between the touch screen and the LCD panel has been melted, now it's time to do your job.
Slowly penetrate the alloy wire between the touch screen and the LCD panel, and move the wire straight down slowly and steadily. DO NOT go back with the alloy wire unless it reaches the end of the phone.
When you reach the end of the phone, go back with the wire. Now the two panel parts should be separated, just remove the LCD panel and you can turn off the machine.