On the new front panel with the adhessive pre-installed, there are perforated area on the blue plastic you can peal away just for the magnets without exposing the rest of the adhesive.

Yes I learned the hard way as well, be sure you leave the yellow plastic tape over the back of the home button and surrounding circuitry or put tape over this area before install. New screen installed and the home button isn't working :-(

I just received a new front planel and the digitizer connector is wrapped in a black electrical tape. I removed to check for the adhesive between circuit and connector but didn't see any, I re-wrapped in the original black tape which I think should be left alone. Also there was a yellow tape over the back of the home button and circuitry between the digitizer cable and home button. I removed this when I removed the blue plastic on the adhesive but I don't think your suppose to. After repair, home button doesn't work which might be because removing that tape.