Best answer my @%^, that answer is just as WRONG as can be. For heaven's sake people, if I'm able to Google "youtube video repair samsung galaxy", you ALL can as well. There are in fact SEVERAL such videos, even done in real time, so you can see it can be done in 15 minutes if you know how to go about it.
Step 1. Order the replacement glass itself, LENS ONLY, not with the digitizer attached... you can order it online for less than $5.
Step 2. While waiting for the replacement glass to arrive, watch 2–3 of the videos, so you're comfortable with the procedure, and get the right type of glue you'll need, which the videos will tell you.
Step 3. Glass arrives and you have your glue... now you'll need a source of heat (hair dryer will do) and a plastic card of some sort, size of a credit card or thereabouts.
Step 4. Now DO IT! Watch the video you liked best one more tube to get into the right mindset, and begin: you're less than a half hour from replacing the cracked lens with a fresh new one. I say "half hour" instead of "15 min" because it's your first time.
Step 5. Celebrate the fact that for about ten bucks and a time investment of a couple hours, you fixed your own %#*@ phone. And the next time someone tells you they're about to spend 200 bucks to fix theirs, tell them to order the glass for you and then you'll do it for them for 50.
That's what you do with your leftover glue. :)