Exercise and nutrition are both important to lose weight and tone up. By toning, what is really meant it building muscle and losing body fat to be able to see the muscle definition.
To do this you need a combination of exercise including weight training and cardio and being in a calorie deficit i.e. eating less calories than what your body needs to maintain it’s current weight.
If you are a beginner I would start off by going to the gym 3x per week and doing a mixture of resistance training and cardio, your training could be 3x full body workouts and 20 minutes cardio for the first few weeks and then progress to make it harder. It’s important to progress with your training as your body will get used to the intensity, so after a few weeks increase the intensity by either increasing your days that you go to the gym or increasing the intensity while you’re in the gym by increasing weights, time or reps.
Also aim to hit 10,000 steps per day and focus on eating 3 smaller meals per day and 1 snack as well as 2 litres of water.
Remember it doesn’t happen overnight, try to focus on enjoying the process rather than focusing on the end goal. It does need to become a lifestyle to make it maintainable, so focus on enjoying your training and food.
Most importantly BE CONSISTENT.