You won't lose it "really quickly". Probably 2lbs a week.
Keto is easy enough but you still gotta count calories.
Split your calorie intake so you get 40% protein 60% fat..
Eat under 30g of carbs a day, and make sure it's only carbs from green veggies and not sugar or starchy food like rice, potatoes, fruit, chocolate, bread.
Longer you're in ketosis the deeper it gets and releases more ketones, you'll burn fat even better.
As you get deeper into keto you become "fat adapted" and stop craving carbs as fat is now your primary fuel.
First few days will be tough without carbs, but after about 5 days you'll stop craving carbs as you'll be fat adapted.
Typical meal for me is "beef steak, 2 fried eggs, mushrooms, loads of raw spinach"
Or "2 chicken breasts, advocado, spring onion mushrooms raw spinach"
I eat cream cheese and normal cheese too. I drink unsweetened almond milk if I want a tasty milk type drink for a treat.
Don't eat too many nuts because they're high calorie and not particularly filling. Nuts wont kick you out of keto.
I eat about 4 meals a day.
You still gotta eat under calorie maintainence to lose weight; but keto will help you feel more full and satisfied. Don't forget to eat green vegetables to help add bulk to your meal and fill you up. Fat and protein together is a filling combination.