Don’t remove the film from the front of acrylic letters. The film protects the front letter surface from scratches during installation.
A bit should be about 3mm dia; just the same diameter as a stud or slightly bigger. First you place a coroplast template on a wall then drill holes through the marks on the coroplast.
Then remove the coroplast template from the wall.
Screw metal studs into plastic washers at the back of house letters and try to install all the parts in the holes first without silicone to check if they fit the holes.
Apply silicone to studs of the parts you are going to install and install the house letter set. Silicone will dry out in few hours.
When done, please send me a photo of your address installed on a wall.