wow that's a lot. Try to not gain more than that or you will have loose skin when you lose weight. nutrition is really important so you have to learn how to eat well, stay away from processed food GMO sugar and snacks. Try to eat organic food. Drink lots of water with lemon. Especially in the morning before breakfast. And do real cardio/work-out not just walking. I wish you all the best with your weight loss journey.
I’m on a low carb diet now. Aiming to lose 0.5kg - 1 kg a week. Insha Allah