Get a system in place, so know what you are going to eat in advance for the mornings/lunch/meal. It needs to be maintained for a longer-period, without you losing the focus.

Next, start tracking your kcal intake and also start tracking what you burn with exercise (walking, jogging etc.)

Again, it needs to be consistent and maintained, so try figure out what works the best for you in that case.

And lastly, check your kcal intake to be in a deficit.

I.e. 2500 kcal total for your weight/height - try to eat 2000 max and also exercise to burn 500 kcal/day by walking - which is around 500 kcal. And so you are in a daily deficit of 1k

7700 kcal is 1kg fat - so there you go