You won't necessarily lose weight through exercise: you can't out-train a bad diet. For weight loss, you need to be calorie deficit.
And you can look at a run "equalling" 300 calories or whatever, but the latest science on this is that it's your basic metabolic rate + your ordinary movement throughout the day which is the more important impact on caloric expenditure.
In other words, get your steps in - try for 15,000 steps per day.
3 kilo dumbbells might help you to get strong, but you'll need to be more creative to get the progressive overload you need. I would recommend not doing your reps too fast. Slow down what's called "time under tension."
Also use body weight exercises. Get a full body press up (no staying on your knees) by doing negatives ie the downward motion. Start from a full arm plank, then aim to very very slowly, get your sternum on the ground. Sternum on the ground before your hips. Then push up as well as you can, keeping your core contracted.
Same with a pull up - use resistance bands and focus on the negative ie get your chin up over the bar however you can, and then let yourself down really slowly - say over 10 counts.