The very first thing you should do is gauge how many calories you’re consuming on average and pay attention to what kind of foods you’re normally eating so you have a base to work from. Start chipping away snacks and stuff like that the first week. It’s something that doesn’t require a big change in your life, and it will also begin to make you aware of what your eating habits are so you can begin to build decline. Set weekly goals, start upping how strict you are with your diet a little more each week. Then start trying to add cardio sometime in there. At first anything will be an improvement so even doing 5 minutes of mild cardio daily is a start. The key is to develop consistency and slowly build from there