Doing high repetitions and low weight in order to burn fat?
Sorry to tell you using 10 lb dumbbells and doing air squats isn’t going to cut it.
Performing lighter weight and higher reps is not going to help you burn more calories and achieve that toned look. To achieve that toned look you need muscle, and in order to gain some muscle you need to lift heavier and work on progressive overload. As for burning more calories the more lean muscle you have on your body, the more you’ll burn at rest.
Progressive overload Is an important factor when it comes to any style of training or form of exercise. It is a principle that involves gradually increasing stress (weight) on the body. In order for muscle to grow, strength to be gained, performance to increase, and burn more calories the human body must be forced to adapt to a tension (stress/weight) that is above and beyond what it has previously experienced. If you stay at the same amount of weight your body is only ever going to be capable of producing that amount of force.

Cool thing about Progressive overload is that it doesn’t always involve going up in weight but can also be applied by adding sets, repetitions, and time.
Example: If you are doing a goblet squat with 30lbs and you continue to lift 30lbs for 3 sets 10 reps for 5 years you’ll never see any new results. Reason why is because the body has adapted to the stress from that exercise. Which is why it’s important to add progressive overload. A way to properly incorporate progressive overload is a goblet squat for 3 sets 1st set 30lbs, 2nd set 35lbs, 3rd set 40lbs. If you don’t incorporate heavier sets than your body is used to you will never adapt to heavier weight and increase strength.
Don’t be afraid of the weights! Allow them to empower you to become the strongest version of you!