You work your WHOLE body. The last thing you want is an unbalanced physique, which isn't just ugly, but, can lead to all sorts of physical issues, as well.
2/3 of your lean muscle mass is in your lower body.
Every pound of lean muscle burns 15 to 50 calories (depends which study you want to use) per day, EVERY day. The key to staying lean if you are a man? More muscle. It burns calories just sitting there.
You want to make gains?
1. Rest / recovery
4. Consistency / persistence / time under load.
If you're missing ANY of the above, you'll be shorting your results. Calories are, BY FAR AND ABOVE, the single most important thing.
You should take images of "before."
If you're clueless, find a friend who is an athlete and who has proper instruction, or hire a trainer, the older the better, who has genuine experience and success. Hiring a 20 year old trainer who is 130 pounds isn't in your best interests. Get someone who has a wealth of experience to help you. Stick with basics. You don't need unbalanced exercise. You need calories and loading and recovery.
You'll want to join a nice gym. LA Fitness, Lifetime, 24 Hour are all good choices.