How to apply Galaxy s4 glass adhesive

Hi you all, in few days I will get a replacement glass for my Samsung galaxy s4, that includes an adhesive like this one http://www.ebay.it/itm/3MM-Digitizer-Tou...

Now I know that I'll have to apply an huge adhesive on the back of the glass itself, in order to paste it on the metal frame of the phone.

The question is: it is better to apply that adhesive FIRST on the LCD, and THEN apply the glass, or it's better to apply the adhesive directly on the back of the glass and then make it fit the phone's body?

Thank you in advantage.