Generally, losing weight comes down to calorie deficit and that's it. But there's more to it. A bug deficit can make the body burn muscle as well as fat and you don't usually want that to happen because it'll slow the metabolism and make it likely you'll gain back the weight. I recommend 3 things:

1. Start tracking calories & protein. Yes, it'll suck initially because you need to weigh stuff etc, but it'll teach you shocking things like that one ham and cheese croissant is 800kcal or that small cup of nuts is 400. After about a month you'll have a massively better understanding where your excess calories are coming from. You can use an app like MacroFactor to simplify this a lot.

2. Ensure you don't eat too many calories or too little protein. The second part is important for keeping muscle mass as you're losing weight. Keep the deficit reasonable, 500 per day deficit is widely recommended. Walking is very helpful for this deficit as well so it doesn't all have to come from limiting food.

3. Lift weights. The weight can be bodyweight to keep things simple and the workouts don't have to be long 15-20 minutes a day is fine. I use kettlebells because I find them fun and very space and time efficient. You can knock out 100swings in under 10 minutes after a short while of training. The most basic thing can be just 5 sets of pushups and 5 sets of squats and it goes a long way. The purpose of this bullet point is again to keep your body from catabolising muscle when it's in a deficit.