Ensure the midframe is clean: any glue residue will limit the new adhesive's capacity to stick to the midframe

Carefully apply the front screen adhesive, starting at one end of the phone (top or bottom) and slowly applying it along the midframe edges, on the sides.

Finally, put the new screen in place, pressing it firmly into place.

Be careful: don't press too hard on the earpiece area at the top, as the screen is particularly fragile around the earpiece.

Don't forget to put the information label back in the phone!