You can't target fat. In order to lose "stomach fat" you're just going to have to lose weight all round. Have a 500 calorie deficit if you want to lose weight, and a 500 calorie surplus if you're looking to put on weight, or "bulk". My advice, if you're trying to build on your upper body, would be to start with the 500 surplus, work the shoulders, chest, lats, traps, biceps and tris. Once you feel you've gained a sufficient amount of mass, begin your 500 calorie deficit cut. That way, you'll gain muscle, then you'll lose fat weight to become more "toned".

Swimming. Swimming is good.

Bench is the key for upper body.

>toned

As for your question:
Read the sticky on 4chan's /fit/.

What should I do if I want to attain a very natural-looking physique similar to my favourite mystery solving dog?

Shakeweight is the solution to get toned like Scooby, trust me!

Lift. Start with a good beginner routine like Strong Lifts or Starting Strength. They're both very squat centered so add in some assistance work. For Strong Lifts I suggest doing pullups/chins on Press day, and dips and skull crushers on bench day. Eat A LOT, but not shitty food. Essentially, lean meats (FUCK TON, 200g for lunch and dinner), oats, fruits, eggs (i eat about 4 whole eggs and 9 egg yokes each morning) and whole grains.

This is essentially the info you'll find on /fit/'s sticky, and it's all acurate.

I went from 130lb weakling to 195lbs in 2 years on Strong Lifts, but the strength gains are even more incredible. I went from 135lb squat to 405lbs, 445lb dead lift, 245lb bench.

You know that picture's just a troll right?

You're a special kind of stupid aren't you?

SS being bad is a meme. Creatine being a drug is a meme. It's from /fit/.