Ah, those cursed instructions on the cans. Yes, you will get beer from it....of a sort.
That being said, the key to homebrewing are the wise words of Charlie Papazian. "Relax, and have a homebrew." Enjoy the moment, and odds are you will enjoy the hell out of your first batch. Years from now, you'll look back and chuckle over how terrible the beer must have been, but your taste buds will remember it fondly. I still think of my first beer as the best damn thing I ever tasted...although if someone handed it to me now I would spit it out and run fleeing from it. Memory is a funny thing.
Well, you're in the BN Army now, son, so it's time to snap to and get moving.
Your first homework assignment is to read "How to Brew". If you don't have the book, start off by reading an early edition online at
http://www.howtobrew.com/intro.htmlYou won't regret spending the time reading it. After that, be sure to buy a copy.
Your next mission is to start on batch #2 as soon as you can. Talk to the person behind the counter of your local homebrew shop and tell them honestly where you're at. Don't feel bad about "stupid" questions. They want to help, and there's no shame in starting somewhere. They'll recommend a real kit, and walk you through your next batch. Be sure to ask for advice here! Folks around here might be a bunch of bastards, but god damn if your BN brothers and sisters won't be there to help.
Now, as to specifics.......
Blow off can happen for a number of reasons. The beer fermenting at too high a temp, the yeast, the amount of head space in the ferementer, etc. It happens to everyone, and although messy it's not a problem. Where in your house are you keeping the fermenter?
What I do, when I suspect there's going to be blowoff, is to run a length of plastic tubing from the hole in the top of the fermenter down to a gallon bottle of water. Submerge the end of the tube into the water and you'll be fine.
As for boiling....
Well, the first stage is to ignore those instructions. How to Brew will walk you through the best steps, but here's a simple way to get it going. First, make sure you have some good water. Get the water up to about 175 and pour in the can of extract and about a pound or two of dried extract. Bring it up to a rolling boil, add your hops (all kits need hop additions. It's just the way it is) and cook for about an hour or so. Cool it down as quick as possible (they're expensive, but a wort chiller is the best investment you could possibly make other than an auto-siphon) top off the water to 5 gallons and pitch your yeast. Simple, yeah? Well, obviously there's a great deal more. You're going to want to use some grains in there as soon as possible. It's pretty easy. Grind 'em, put them in a bag and hang the bag in your wort just like you were making tea. You're going to want to play around with your recipes. You're going to want to play around temperature control, and you're going to want to play around a dozen other things as you work on perfecting your process. It's a long journey, but the neat thing is that it's fun to travel it.
Never get discouraged and, of course, "relax and have a homebrew"
For your next batch, tell us exactly what ingredients you have, and what your process is going to be. We'll be happy to guide you through.
I've only been brewing since May and I've recently switched over to all grain. Now, I brewed a very large number of batches, but I went from "follow the instructions on the can" to being able to make beers that people really love. I have people who buy beer off me, people who look forward to my beers, and rave reviews. You get there with practice and with having an open mind ot learning. Every brewer you meet can teach you something. Good luck, man!