You are burning fat right now, just sitting and reading, but not very much. Your body constantly uses fat to support all the activities going on.
The issue is How Much? And if you want to reduce the amount of fat on your body, what is your caloric balance [how many calories you consume vs. calories used]? At least half of the calories used during the day are fat calories from food and your fat cells. If you are at caloric equilibrium, your fat cells will be gaining and losing about the same every day.
If you are in a caloric deficit, you will be burning stored fat immediately. If you exercise moderately and burn 400 calories in one hour above your normal caloric intake, roughly half the calories burned during exercise are fat calories and half stored carbohydrate calories.
However, if this is done consistently, you always restore the stored carbs as glycogen and shift your metabolism slightly towards burning more fat at rest, so that the net effect over a number of days is burning slightly less than 400 fat calories at rest and the remainder is protein.
Doing strength training will minimize the protein calories used. Just lowering your caloric intake by 400 calories will shift your metabolism towards metabolizing more protein relative to fat.
Example: To give you an approximate estimate of fat loss in pounds, roughly 3500calories are in one pound of fat [or 7700calories per kilogram]. Therefore about 9 days of a caloric deficit of 400 calories/day will cause you to lose one pound of fat or about 20 days to lose one kg of fat. If you weigh yourself, this does not mean one pound of body weight because there will be an indeterminate of water loss depending on what you eat and how well you hydrate.
"All the best"