Thats is not sound advice in regards to junk food. The issue is that junk food is energy dense. Indeed the general trend is that the higher the degree of processed food, the more energy dense they usually are. But obvious foods like soft drink and burgers are high in sugar, salt and fat. There is an enormous research base linking obesity to junk foods so it would be advisable the OP shifts from that diet as it is well acknowledged as being unhealthy. Instead he should shift to a fresh food diet.
To the OP - The answer isnt complex. Start with throwing out what you know to be junk foods - they are high in sugar and youre never going to use the calories so they will simply be stored as fat.
Next just eat normal portions and choose fresh foods with good proportions of fruit and vegetable. DONT snack. Three meals a day and no more. reduce high starch foods as they once again are energy dense.
lastly exercise - set yourself up to be a winner and just do what you know you will be achieved - maybe thats just walking around the block quickly. HOWEVER once you can easily achieve you have to up the level and exercise for longer or more strenuously.
please take note of the abundance evidence available in your country. The USA has one of the highest obesity rates in the world. learn from the mistakes made by others and choose not to go down their path.
One last thing. Consuming high-fat foods contributes to atherosclerosis - thats where fat deposits line blood vessels. If you continue having a high fat diet, not only is obesity a problem, but you're at higher risk of heart disease and stroke. Salt in your diet is fine but a junk food diet is way to high a salt intake. It greatly increases your risks associated with stroke and heart attack when coupled with atherosclerosis.
So easy - a little exercise - fresh foods - NO SODA - normal portions. You'll get there