So is it recommended to run or is it better to do those exercises, or both..(whew..that'll be exhausting for me)?
Exhausting is good, how else is it supposed to work?

Muscles need an impulse to grow, they have to be challenged to the best amount possible. This is best done with the proper exercises, because they make sure that all the strain works on the muscles. If you don't execute them properly, a lot of the impulse will often go on bones and sinews, which obviously isn't healthy, will hurt and will minimise the training effect.
An example for dumbell training: The dumbell has to be lowered very slowly. That's really working on the muscle. If you drop it quickly instead, that has two negative side effects:
-It won't be a slow, constant strain anymore, but a sudden peak when you catch the weigth again. This goes on links, bones and isn't good for the muscle at all
-Muscles get the most impulse when they're working without a single break and go into the unaerobic area (I'm not certain if I use the right term here, but 100% about the method)
Especially for simple excerises like dumbell counts: Do as many repertitions once you're in the area when you actually think that you can't do a single one anymore. It's a common technique to have somebody slightly assisting your movements, once your muscles can't work anymore, to have the best training effect. But always make sure to do proper movements.
Also, muscles are better in countermotion than in motion. Even if you can't raise a dumbell another time, the muscles will still be able to slower the downwards motion. Let's say you're using a dumbell on one side only and the biceps is totally at it's limit already, you can assist the upwards motion with your other arm, and only let the biceps do the downwards motion.
If you really can't do both at once, then better start with running or biking for stamina, until you got used to that part, before adding muscle exercises.
Let's just say it's good that you've been drinking sugar drinks up until now. Dropping them already lowers the amount of useless calories you're gaining instantly
