Find the book "Starting Strength: Basic Barbell Training" by Mark Rippetoe. Follow his guidelines, and in about 12 to 18 months, you'll be a competitive bodybuilder. I've followed his formula, for the most part, and I've managed to add quite a bit of mass over the past three months. My chest, back, legs, arms and abs show a lot of growth and definition. Whats more the workouts he proposes are just the basic stuff and are fun! I really enjoy lifting more now than ever!
Just basic bench press, squats, dead lifts, power cleans, and standing press. They hit all the major, and minor muscle groups. Add a little more weight to the bar each week. You have to push yourself a little, but as I found out, as the results become noticeable, it gets easier. I run about a mile on the treadmill to warm up and on off days will fill in with cardio and do some light reps just for fun.
I also installed an app on my iPhone to keep track of my workouts. This has helped a great deal also. Do a search for those and find one you like.
Also, search the New York Times Health section for an article titled "Fitness Crazed" published May 24 2014 by Daniel Duane. Reading that is what inspired me.
Start working out, and have fun!