So to answer your question regarding working out your entire body with just a pair of dumbbells. The answer is yes. You definitely can. I'll do you one better by giving you an exercise that trains each and every one of your muscle groups!
Can dumbbells build muscle fast?
"Dumbbell complexes that target large muscle groups can stimulate more muscle fibers and speed up fat loss," he says. Do this: Perform the circuit four times. For the first circuit, do 12 reps of each exercise. Then do 10 reps for the second, 8 for the third, and 6 for the fourth.